-- initial states
local Option = {
	-- can modify objects
	Modifiable = true;
	-- can select objects
	Selectable = true;
}

-- general size of GUI objects, in pixels
local GUI_SIZE = 16
-- padding between items within each entry
local ENTRY_PADDING = 1
-- padding between each entry
local ENTRY_MARGIN = 1

--[[

# Explorer Panel

A GUI panel that displays the game hierarchy.


## Selection Bindables

- `Function GetSelection ( )`

	Returns an array of objects representing the objects currently
	selected in the panel.

- `Function SetSelection ( Objects selection )`

	Sets the objects that are selected in the panel. `selection` is an array
	of objects.

- `Event SelectionChanged ( )`

	Fired after the selection changes.


## Option Bindables

- `Function GetOption ( string optionName )`

	If `optionName` is given, returns the value of that option. Otherwise,
	returns a table of options and their current values.

- `Function SetOption ( string optionName, bool value )`

	Sets `optionName` to `value`.

	Options:

	- Modifiable

		Whether objects can be modified by the panel.

		Note that modifying objects depends on being able to select them. If
		Selectable is false, then Actions will not be available. Reparenting
		is still possible, but only for the dragged object.

	- Selectable

		Whether objects can be selected.

		If Modifiable is false, then left-clicking will perform a drag
		selection.

## Updates

- 2013-09-14
	- Added GetOption and SetOption bindables.
		- Option: Modifiable; sets whether objects can be modified by the panel.
		- Option: Selectable; sets whether objects can be selected.
	- Slight modification to left-click selection behavior.
	- Improved layout and scaling.

- 2013-09-13
	- Added drag to reparent objects.
		- Left-click to select/deselect object.
		- Left-click and drag unselected object to reparent single object.
		- Left-click and drag selected object to move reparent entire selection.
		- Right-click while dragging to cancel.

- 2013-09-11
	- Added explorer panel header with actions.
		- Added Cut action.
		- Added Copy action.
		- Added Paste action.
		- Added Delete action.
	- Added drag selection.
		- Left-click: Add to selection on drag.
		- Right-click: Add to or remove from selection on drag.
	- Ensured SelectionChanged fires only when the selection actually changes.
	- Added documentation and change log.
	- Fixed thread issue.

- 2013-09-09
	- Added basic multi-selection.
		- Left-click to set selection.
		- Right-click to add to or remove from selection.
	- Removed "Selection" ObjectValue.
		- Added GetSelection BindableFunction.
		- Added SetSelection BindableFunction.
		- Added SelectionChanged BindableEvent.
	- Changed font to SourceSans.

- 2013-08-31
	- Improved GUI sizing based off of `GUI_SIZE` constant.
	- Automatic font size detection.

- 2013-08-27
	- Initial explorer panel.


## Todo

- Sorting
	- by ExplorerOrder
	- by children
	- by name
- Drag objects to reparent

]]

local ENTRY_SIZE = GUI_SIZE + ENTRY_PADDING*2
local ENTRY_BOUND = ENTRY_SIZE + ENTRY_MARGIN
local HEADER_SIZE = ENTRY_SIZE

local FONT = 'SourceSans'
local FONT_SIZE do
	local size = {8,9,10,11,12,14,18,24,36,48}
	local s
	local n = math.huge
	for i = 1,#size do
		if size[i] <= GUI_SIZE then
			FONT_SIZE = i - 1
		end
	end
end

local GuiColor = {
	Background      = Color3.new(233/255, 233/255, 233/255);
	Border          = Color3.new(149/255, 149/255, 149/255);
	Selected        = Color3.new( 96/255, 140/255, 211/255);
	BorderSelected  = Color3.new( 86/255, 125/255, 188/255);
	Text            = Color3.new(  0/255,   0/255,   0/255);
	TextDisabled    = Color3.new(128/255, 128/255, 128/255);
	TextSelected    = Color3.new(255/255, 255/255, 255/255);
	Button          = Color3.new(221/255, 221/255, 221/255);
	ButtonBorder    = Color3.new(149/255, 149/255, 149/255);
	ButtonSelected  = Color3.new(255/255,   0/255,   0/255);
	Field           = Color3.new(255/255, 255/255, 255/255);
	FieldBorder     = Color3.new(191/255, 191/255, 191/255);
	TitleBackground = Color3.new(178/255, 178/255, 178/255);
}

----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
---- Icon map constants

local MAP_ID = 129293660

-- Indices based on implementation of Icon function.
local ACTION_CUT         = 160
local ACTION_COPY        = 161
local ACTION_PASTE       = 162
local ACTION_DELETE      = 163
local ACTION_SORT        = 164
local ACTION_CUT_OVER    = 174
local ACTION_COPY_OVER   = 175
local ACTION_PASTE_OVER  = 176
local ACTION_DELETE_OVER = 177
local ACTION_SORT_OVER   = 178

local NODE_COLLAPSED      = 165
local NODE_EXPANDED       = 166
local NODE_COLLAPSED_OVER = 179
local NODE_EXPANDED_OVER  = 180

local ExplorerIndex = {
    Accoutrement                     = 32;
    AdvancedDragger                  =  0;
    Animation                        = 60;
    AnimationTrack                   = 60;
    AnimationTrackState              = 60;
    Animator                         =  0;
    ArcHandles                       = 56;
    Authoring                        =  3;
    Backpack                         = 20;
    BackpackItem                     =  0;
    BadgeService                     =  0;
    BasePart                         =  1;
    BasePlayerGui                    = 46;
    BaseScript                       =  6;
    BevelMesh                        =  8;
    BillboardGui                     = 64;
    BindableEvent                    = 67;
    BindableFunction                 = 66;
    BlockMesh                        =  8;
    BodyAngularVelocity              = 14;
    BodyColors                       =  0;
    BodyForce                        = 14;
    BodyGyro                         = 14;
    BodyMover                        = 14;
    BodyPosition                     = 14;
    BodyThrust                       = 14;
    BodyVelocity                     = 14;
    BoolValue                        =  4;
    BrickColorValue                  =  4;
    Button                           =  0;
    ButtonBindingWidget              =  0;
    CFrameValue                      =  4;
    CacheableContentProvider         =  0;
    Camera                           =  5;
    ChangeHistoryService             =  0;
    CharacterAppearance              =  0;
    CharacterMesh                    = 60;
    Chat                             =  0;
    ClickDetector                    = 41;
    Clothing                         = 40;
    CollectionService                =  0;
    Color3Value                      =  4;
    Configuration                    = 58;
    ContentFilter                    =  0;
    ContentProvider                  =  0;
    ContextActionService             =  0;
    Controller                       =  0;
    ControllerService                =  0;
    CookiesService                   =  0;
    CoreGui                          =  0;
    CoreScript                       =  6;
    CornerWedgePart                  =  1;
    CustomEvent                      =  4;
    CustomEventReceiver              =  4;
    CylinderMesh                     =  8;
    DataModel                        =  0;
    DataModelMesh                    =  8;
    Debris                           = 30;
    DebugSettings                    =  3;
    DebuggerBreakpoint               =  0;
    DebuggerService                  =  0;
    DebuggerWatch                    =  0;
    Decal                            =  7;
    Dialog                           = 62;
    DialogChoice                     = 63;
    DoubleConstrainedValue           =  4;
    Dragger                          =  0;
    DynamicRotate                    = 34;
    Explosion                        = 36;
    FWService                        =  0;
    FaceInstance                     =  0;
    FastLogSettings                  =  3;
    Feature                          =  0;
    FileMesh                         =  8;
    Fire                             = 61;
    Flag                             = 38;
    FlagStand                        = 39;
    FlagStandService                 =  0;
    FloorWire                        =  4;
    ForceField                       = 37;
    FormFactorPart                   =  1;
    Frame                            = 48;
    FriendService                    =  0;
    FunctionalTest                   =  0;
    GamePassService                  =  0;
    GameSettings                     =  3;
    GenericSettings                  =  3;
    Geometry                         =  0;
    GlobalSettings                   =  3;
    Glue                             = 34;
    GuiBase                          = 47;
    GuiBase2d                        =  0;
    GuiBase3d                        =  0;
    GuiButton                        = 51;
    GuiItem                          =  0;
    GuiLabel                         = 50;
    GuiMain                          = 47;
    GuiObject                        = 48;
    GuiRoot                          =  0;
    GuiService                       =  0;
    GuidRegistryService              =  0;
    Handles                          = 53;
    HandlesBase                      =  0;
    Hat                              = 45;
    Hint                             = 33;
    Hole                             =  0;
    Hopper                           =  0;
    HopperBin                        = 22;
    Humanoid                         =  9;
    HumanoidController               =  0;
    ImageButton                      = 52;
    ImageLabel                       = 49;
    InsertService                    =  0;
    Instance                         =  0;
    InstancePacketCache              =  0;
    IntConstrainedValue              =  4;
    IntValue                         =  4;
    JointInstance                    = 34;
    JointsService                    =  0;
    Keyframe                         = 60;
    KeyframeSequence                 =  0;
    KeyframeSequenceProvider         =  0;
    LayerCollector                   =  0;
    Light                            =  0;
    Lighting                         = 13;
    LoadingGui                       = 46;
    LocalBackpack                    =  0;
    LocalScript                      = 18;
    LocalWorkspace                   =  0;
    LuaSettings                      =  3;
    LuaWebService                    =  0;
    ManualGlue                       = 34;
    ManualSurfaceJointInstance       =  0;
    ManualWeld                       = 34;
    MarketplaceService               =  0;
    MeshContentProvider              =  0;
    Message                          = 33;
    Model                            =  2;
    Motor                            = 34;
    Motor6D                          = 34;
    MotorFeature                     =  0;
    Mouse                            =  0;
    NetworkClient                    = 16;
    NetworkMarker                    =  0;
    NetworkPeer                      =  0;
    NetworkReplicator                = 29;
    NetworkServer                    = 15;
    NetworkSettings                  =  3;
    NotificationBox                  = 48;
    NotificationObject               = 48;
    NumberValue                      =  4;
    ObjectValue                      =  4;
    PVAdornment                      =  0;
    PVInstance                       =  0;
    Pants                            = 44;
    ParallelRampPart                 =  1;
    Part                             =  1;
    PartAdornment                    =  0;
    PersonalServerService            =  0;
    PhysicsPacketCache               =  0;
    PhysicsService                   =  0;
    PhysicsSettings                  =  3;
    Platform                         =  1;
    Player                           = 12;
    PlayerGui                        = 46;
    PlayerHUD                        =  0;
    PlayerMouse                      =  0;
    Players                          = 21;
    Plugin                           =  0;
    PluginManager                    =  0;
    PluginMouse                      =  0;
    PointLight                       =  0;
    Pose                             = 60;
    PrismPart                        =  1;
    ProfilingItem                    =  0;
    PyramidPart                      =  1;
    RayValue                         =  4;
    ReflectionMetadata               =  0;
    ReflectionMetadataCallbacks      =  0;
    ReflectionMetadataClass          =  0;
    ReflectionMetadataClasses        =  0;
    ReflectionMetadataEvents         =  0;
    ReflectionMetadataFunctions      =  0;
    ReflectionMetadataItem           =  0;
    ReflectionMetadataMember         =  0;
    ReflectionMetadataProperties     =  0;
    ReflectionMetadataYieldFunctions =  0;
    RenderHooksService               =  0;
    RenderSettings                   =  3;
    RightAngleRampPart               =  1;
    RocketPropulsion                 = 14;
    RootInstance                     =  0;
    Rotate                           = 34;
    RotateP                          = 34;
    RotateV                          = 34;
    RunService                       =  0;
    RunningAverageItemDouble         =  0;
    RunningAverageItemInt            =  0;
    RuntimeScriptService             =  0;
    Scale9Frame                      =  0;
    ScreenGui                        = 47;
    Script                           =  6;
    ScriptContext                    =  0;
    ScriptDebugger                   =  0;
    ScriptInformationProvider        =  0;
    ScriptService                    =  0;
    Seat                             = 35;
    Selection                        =  0;
    SelectionBox                     = 54;
    SelectionLasso                   = 57;
    SelectionPartLasso               = 57;
    SelectionPointLasso              = 57;
    ServerReplicator                 =  0;
    ServiceProvider                  =  0;
    Shirt                            = 43;
    ShirtGraphic                     = 40;
    SkateboardController             =  0;
    SkateboardPlatform               =  1;
    Skin                             =  0;
    Sky                              = 28;
    Smoke                            = 59;
    Snap                             = 34;
    SocialService                    =  0;
    Sound                            = 11;
    SoundService                     = 31;
    Sparkles                         = 42;
    SpawnLocation                    = 25;
    SpawnerService                   =  0;
    SpecialMesh                      =  8;
    SpotLight                        =  0;
    StarterGear                      = 20;
    StarterGui                       = 46;
    StarterPack                      = 20;
    StarterScript                    = 18;
    Stats                            =  0;
    StatsItem                        =  0;
    Status                           =  2;
    StockSound                       = 11;
    StringValue                      =  4;
    StudioTool                       =  0;
    SurfaceSelection                 = 55;
    TaskScheduler                    =  0;
    Team                             = 24;
    Teams                            = 23;
    TeleportService                  =  0;
    Terrain                          = 65;
    TestService                      = 68;
    TextBox                          = 51;
    TextButton                       = 51;
    TextLabel                        = 50;
    TextService                      =  0;
    Texture                          = 10;
    TextureContentProvider           =  0;
    TextureTrail                     =  4;
    TimerService                     =  0;
    Tool                             = 17;
    Toolbar                          =  0;
    TotalCountTimeIntervalItem       =  0;
    TouchTransmitter                 = 37;
    TrussPart                        =  1;
    TweenService                     =  0;
    UserGameSettings                 =  4;
    UserInputService                 =  0;
    UserSettings                     =  3;
    Vector3Value                     =  4;
    VehicleController                =  0;
    VehicleSeat                      = 35;
    VelocityMotor                    = 34;
    VirtualUser                      =  0;
    Visit                            =  0;
    WedgePart                        =  1;
    Weld                             = 34;
    Workspace                        = 19;
}

----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------

function Create(ty,data)
	local obj
	if type(ty) == 'string' then
		obj = Instance.new(ty)
	else
		obj = ty
	end
	for k, v in pairs(data) do
		if type(k) == 'number' then
			v.Parent = obj
		else
			obj[k] = v
		end
	end
	return obj
end

-- Connects a function to an event such that it fires asynchronously
function Connect(event,func)
	return event:connect(function(...)
		local a = {...}
		Spawn(function() func(unpack(a)) end)
	end)
end

-- returns the ascendant ScreenGui of an object
function GetScreen(screen)
	if screen == nil then return nil end
	while not screen:IsA("ScreenGui") do
		screen = screen.Parent
		if screen == nil then return nil end
	end
	return screen
end

do
	local ZIndexLock = {}
	-- Sets the ZIndex of an object and its descendants. Objects are locked so
	-- that SetZIndexOnChanged doesn't spawn multiple threads that set the
	-- ZIndex of the same object.
	function SetZIndex(object,z)
		if not ZIndexLock[object] then
			ZIndexLock[object] = true
			if object:IsA'GuiObject' then
				object.ZIndex = z
			end
			local children = object:GetChildren()
			for i = 1,#children do
				SetZIndex(children[i],z)
			end
			ZIndexLock[object] = nil
		end
	end

	function SetZIndexOnChanged(object)
		return object.Changed:connect(function(p)
			if p == "ZIndex" then
				SetZIndex(object,object.ZIndex)
			end
		end)
	end
end

---- IconMap ----
-- Image size: 256px x 256px
-- Icon size: 16px x 16px
-- Padding between each icon: 2px
-- Padding around image edge: 1px
-- Total icons: 14 x 14 (196)
local Icon do
	local iconMap = 'http://www.roblox.com/asset/?id=' .. MAP_ID
	Game:GetService('ContentProvider'):Preload(iconMap)
	local iconDehash do
		-- 14 x 14, 0-based input, 0-based output
		local f=math.floor
		function iconDehash(h)
			return f(h/14%14),f(h%14)
		end
	end

	function Icon(IconFrame,index)
		local row,col = iconDehash(index)
		local mapSize = Vector2.new(256,256)
		local pad,border = 2,1
		local iconSize = 16

		local class = 'Frame'
		if type(IconFrame) == 'string' then
			class = IconFrame
			IconFrame = nil
		end

		if not IconFrame then
			IconFrame = Create(class,{
				Name = "Icon";
				BackgroundTransparency = 1;
				ClipsDescendants = true;
				Create('ImageLabel',{
					Name = "IconMap";
					Active = false;
					BackgroundTransparency = 1;
					Image = iconMap;
					Size = UDim2.new(mapSize.x/iconSize,0,mapSize.y/iconSize,0);
				});
			})
		end

		IconFrame.IconMap.Position = UDim2.new(-col - (pad*(col+1) + border)/iconSize,0,-row - (pad*(row+1) + border)/iconSize,0)
		return IconFrame
	end
end

----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
---- ScrollBar
do
	-- AutoButtonColor doesn't always reset properly
	local function ResetButtonColor(button)
		local active = button.Active
		button.Active = not active
		button.Active = active
	end

	local function ArrowGraphic(size,dir,scaled,template)
		local Frame = Create('Frame',{
			Name = "Arrow Graphic";
			BorderSizePixel = 0;
			Size = UDim2.new(0,size,0,size);
			Transparency = 1;
		})
		if not template then
			template = Instance.new("Frame")
			template.BorderSizePixel = 0
		end

		local transform
		if dir == nil or dir == 'Up' then
			function transform(p,s) return p,s end
		elseif dir == 'Down' then
			function transform(p,s) return UDim2.new(0,p.X.Offset,0,size-p.Y.Offset-1),s end
		elseif dir == 'Left' then
			function transform(p,s) return UDim2.new(0,p.Y.Offset,0,p.X.Offset),UDim2.new(0,s.Y.Offset,0,s.X.Offset) end
		elseif dir == 'Right' then
			function transform(p,s) return UDim2.new(0,size-p.Y.Offset-1,0,p.X.Offset),UDim2.new(0,s.Y.Offset,0,s.X.Offset) end
		end

		local scale
		if scaled then
			function scale(p,s) return UDim2.new(p.X.Offset/size,0,p.Y.Offset/size,0),UDim2.new(s.X.Offset/size,0,s.Y.Offset/size,0) end
		else
			function scale(p,s) return p,s end
		end

		local o = math.floor(size/4)
		if size%2 == 0 then
			local n = size/2-1
			for i = 0,n do
				local t = template:Clone()
				local p,s = scale(transform(
					UDim2.new(0,n-i,0,o+i),
					UDim2.new(0,(i+1)*2,0,1)
				))
				t.Position = p
				t.Size = s
				t.Parent = Frame
			end
		else
			local n = (size-1)/2
			for i = 0,n do
				local t = template:Clone()
				local p,s = scale(transform(
					UDim2.new(0,n-i,0,o+i),
					UDim2.new(0,i*2+1,0,1)
				))
				t.Position = p
				t.Size = s
				t.Parent = Frame
			end
		end
		if size%4 > 1 then
			local t = template:Clone()
			local p,s = scale(transform(
				UDim2.new(0,0,0,size-o-1),
				UDim2.new(0,size,0,1)
			))
			t.Position = p
			t.Size = s
			t.Parent = Frame
		end
		return Frame
	end


	local function GripGraphic(size,dir,spacing,scaled,template)
		local Frame = Create('Frame',{
			Name = "Grip Graphic";
			BorderSizePixel = 0;
			Size = UDim2.new(0,size.x,0,size.y);
			Transparency = 1;
		})
		if not template then
			template = Instance.new("Frame")
			template.BorderSizePixel = 0
		end

		spacing = spacing or 2

		local scale
		if scaled then
			function scale(p) return UDim2.new(p.X.Offset/size.x,0,p.Y.Offset/size.y,0) end
		else
			function scale(p) return p end
		end

		if dir == 'Vertical' then
			for i=0,size.x-1,spacing do
				local t = template:Clone()
				t.Size = scale(UDim2.new(0,1,0,size.y))
				t.Position = scale(UDim2.new(0,i,0,0))
				t.Parent = Frame
			end
		elseif dir == nil or dir == 'Horizontal' then
			for i=0,size.y-1,spacing do
				local t = template:Clone()
				t.Size = scale(UDim2.new(0,size.x,0,1))
				t.Position = scale(UDim2.new(0,0,0,i))
				t.Parent = Frame
			end
		end

		return Frame
	end

	local mt = {
		__index = {
			GetScrollPercent = function(self)
				return self.ScrollIndex/(self.TotalSpace-self.VisibleSpace)
			end;
			CanScrollDown = function(self)
				return self.ScrollIndex + self.VisibleSpace < self.TotalSpace
			end;
			CanScrollUp = function(self)
				return self.ScrollIndex > 0
			end;
			ScrollDown = function(self)
				self.ScrollIndex = self.ScrollIndex + self.PageIncrement
				self:Update()
			end;
			ScrollUp = function(self)
				self.ScrollIndex = self.ScrollIndex - self.PageIncrement
				self:Update()
			end;
			ScrollTo = function(self,index)
				self.ScrollIndex = index
				self:Update()
			end;
			SetScrollPercent = function(self,percent)
				self.ScrollIndex = math.floor((self.TotalSpace - self.VisibleSpace)*percent + 0.5)
				self:Update()
			end;
		};
	}
	mt.__index.CanScrollRight = mt.__index.CanScrollDown
	mt.__index.CanScrollLeft = mt.__index.CanScrollUp
	mt.__index.ScrollLeft = mt.__index.ScrollUp
	mt.__index.ScrollRight = mt.__index.ScrollDown

	function ScrollBar(horizontal)
		-- create row scroll bar
		local ScrollFrame = Create('Frame',{
			Name = "ScrollFrame";
			Position = horizontal and UDim2.new(0,0,1,-GUI_SIZE) or UDim2.new(1,-GUI_SIZE,0,0);
			Size = horizontal and UDim2.new(1,0,0,GUI_SIZE) or UDim2.new(0,GUI_SIZE,1,0);
			BackgroundTransparency = 1;
			Create('ImageButton',{
				Name = "ScrollDown";
				Position = horizontal and UDim2.new(1,-GUI_SIZE,0,0) or UDim2.new(0,0,1,-GUI_SIZE);
				Size = UDim2.new(0, GUI_SIZE, 0, GUI_SIZE);
				BackgroundColor3 = GuiColor.Button;
				BorderColor3 = GuiColor.Border;
				--BorderSizePixel = 0;
			});
			Create('ImageButton',{
				Name = "ScrollUp";
				Size = UDim2.new(0, GUI_SIZE, 0, GUI_SIZE);
				BackgroundColor3 = GuiColor.Button;
				BorderColor3 = GuiColor.Border;
				--BorderSizePixel = 0;
			});
			Create('ImageButton',{
				Name = "ScrollBar";
				Size = horizontal and UDim2.new(1,-GUI_SIZE*2,1,0) or UDim2.new(1,0,1,-GUI_SIZE*2);
				Position = horizontal and UDim2.new(0,GUI_SIZE,0,0) or UDim2.new(0,0,0,GUI_SIZE);
				AutoButtonColor = false;
				BackgroundColor3 = Color3.new(0.94902, 0.94902, 0.94902);
				BorderColor3 = GuiColor.Border;
				--BorderSizePixel = 0;
				Create('ImageButton',{
					Name = "ScrollThumb";
					AutoButtonColor = false;
					Size = UDim2.new(0, GUI_SIZE, 0, GUI_SIZE);
					BackgroundColor3 = GuiColor.Button;
					BorderColor3 = GuiColor.Border;
					--BorderSizePixel = 0;
				});
			});
		})

		local graphicTemplate = Create('Frame',{
			Name="Graphic";
			BorderSizePixel = 0;
			BackgroundColor3 = GuiColor.Border;
		})
		local graphicSize = GUI_SIZE/2

		local ScrollDownFrame = ScrollFrame.ScrollDown
			local ScrollDownGraphic = ArrowGraphic(graphicSize,horizontal and 'Right' or 'Down',true,graphicTemplate)
			ScrollDownGraphic.Position = UDim2.new(0.5,-graphicSize/2,0.5,-graphicSize/2)
			ScrollDownGraphic.Parent = ScrollDownFrame
		local ScrollUpFrame = ScrollFrame.ScrollUp
			local ScrollUpGraphic = ArrowGraphic(graphicSize,horizontal and 'Left' or 'Up',true,graphicTemplate)
			ScrollUpGraphic.Position = UDim2.new(0.5,-graphicSize/2,0.5,-graphicSize/2)
			ScrollUpGraphic.Parent = ScrollUpFrame
		local ScrollBarFrame = ScrollFrame.ScrollBar
		local ScrollThumbFrame = ScrollBarFrame.ScrollThumb
		do
			local size = GUI_SIZE*3/8
			local Decal = GripGraphic(Vector2.new(size,size),horizontal and 'Vertical' or 'Horizontal',2,graphicTemplate)
			Decal.Position = UDim2.new(0.5,-size/2,0.5,-size/2)
			Decal.Parent = ScrollThumbFrame
		end

		local Class = setmetatable({
			GUI = ScrollFrame;
			ScrollIndex = 0;
			VisibleSpace = 0;
			TotalSpace = 0;
			PageIncrement = 1;
		},mt)

		local UpdateScrollThumb
		if horizontal then
			function UpdateScrollThumb()
				ScrollThumbFrame.Size = UDim2.new(Class.VisibleSpace/Class.TotalSpace,0,0,GUI_SIZE)
				if ScrollThumbFrame.AbsoluteSize.x < GUI_SIZE then
					ScrollThumbFrame.Size = UDim2.new(0,GUI_SIZE,0,GUI_SIZE)
				end
				local barSize = ScrollBarFrame.AbsoluteSize.x
				ScrollThumbFrame.Position = UDim2.new(Class:GetScrollPercent()*(barSize - ScrollThumbFrame.AbsoluteSize.x)/barSize,0,0,0)
			end
		else
			function UpdateScrollThumb()
				ScrollThumbFrame.Size = UDim2.new(0,GUI_SIZE,Class.VisibleSpace/Class.TotalSpace,0)
				if ScrollThumbFrame.AbsoluteSize.y < GUI_SIZE then
					ScrollThumbFrame.Size = UDim2.new(0,GUI_SIZE,0,GUI_SIZE)
				end
				local barSize = ScrollBarFrame.AbsoluteSize.y
				ScrollThumbFrame.Position = UDim2.new(0,0,Class:GetScrollPercent()*(barSize - ScrollThumbFrame.AbsoluteSize.y)/barSize,0)
			end
		end

		local lastDown
		local lastUp
		local scrollStyle = {BackgroundColor3=GuiColor.Border,BackgroundTransparency=0}
		local scrollStyle_ds = {BackgroundColor3=GuiColor.Border,BackgroundTransparency=0.7}

		local function Update()
			local t = Class.TotalSpace
			local v = Class.VisibleSpace
			local s = Class.ScrollIndex
			if v <= t then
				if s > 0 then
					if s + v > t then
						Class.ScrollIndex = t - v
					end
				else
					Class.ScrollIndex = 0
				end
			else
				Class.ScrollIndex = 0
			end

			if Class.UpdateCallback then
				if Class.UpdateCallback(Class) == false then
					return
				end
			end

			local down = Class:CanScrollDown()
			local up = Class:CanScrollUp()
			if down ~= lastDown then
				lastDown = down
				ScrollDownFrame.Active = down
				ScrollDownFrame.AutoButtonColor = down
				local children = ScrollDownGraphic:GetChildren()
				local style = down and scrollStyle or scrollStyle_ds
				for i = 1,#children do
					Create(children[i],style)
				end
			end
			if up ~= lastUp then
				lastUp = up
				ScrollUpFrame.Active = up
				ScrollUpFrame.AutoButtonColor = up
				local children = ScrollUpGraphic:GetChildren()
				local style = up and scrollStyle or scrollStyle_ds
				for i = 1,#children do
					Create(children[i],style)
				end
			end
			ScrollThumbFrame.Visible = down or up
			UpdateScrollThumb()
		end
		Class.Update = Update

		SetZIndexOnChanged(ScrollFrame)

		local MouseDrag = Create('ImageButton',{
			Name = "MouseDrag";
			Position = UDim2.new(-0.25,0,-0.25,0);
			Size = UDim2.new(1.5,0,1.5,0);
			Transparency = 1;
			AutoButtonColor = false;
			Active = true;
			ZIndex = 10;
		})

		local scrollEventID = 0
		ScrollDownFrame.MouseButton1Down:connect(function()
			scrollEventID = tick()
			local current = scrollEventID
			local up_con
			up_con = MouseDrag.MouseButton1Up:connect(function()
				scrollEventID = tick()
				MouseDrag.Parent = nil
				ResetButtonColor(ScrollDownFrame)
				up_con:disconnect(); drag = nil
			end)
			MouseDrag.Parent = GetScreen(ScrollFrame)
			Class:ScrollDown()
			wait(0.2) -- delay before auto scroll
			while scrollEventID == current do
				Class:ScrollDown()
				if not Class:CanScrollDown() then break end
				wait()
			end
		end)

		ScrollDownFrame.MouseButton1Up:connect(function()
			scrollEventID = tick()
		end)

		ScrollUpFrame.MouseButton1Down:connect(function()
			scrollEventID = tick()
			local current = scrollEventID
			local up_con
			up_con = MouseDrag.MouseButton1Up:connect(function()
				scrollEventID = tick()
				MouseDrag.Parent = nil
				ResetButtonColor(ScrollUpFrame)
				up_con:disconnect(); drag = nil
			end)
			MouseDrag.Parent = GetScreen(ScrollFrame)
			Class:ScrollUp()
			wait(0.2)
			while scrollEventID == current do
				Class:ScrollUp()
				if not Class:CanScrollUp() then break end
				wait()
			end
		end)

		ScrollUpFrame.MouseButton1Up:connect(function()
			scrollEventID = tick()
		end)

		if horizontal then
			ScrollBarFrame.MouseButton1Down:connect(function(x,y)
				scrollEventID = tick()
				local current = scrollEventID
				local up_con
				up_con = MouseDrag.MouseButton1Up:connect(function()
					scrollEventID = tick()
					MouseDrag.Parent = nil
					ResetButtonColor(ScrollUpFrame)
					up_con:disconnect(); drag = nil
				end)
				MouseDrag.Parent = GetScreen(ScrollFrame)
				if x > ScrollThumbFrame.AbsolutePosition.x then
					Class:ScrollTo(Class.ScrollIndex + Class.VisibleSpace)
					wait(0.2)
					while scrollEventID == current do
						if x < ScrollThumbFrame.AbsolutePosition.x + ScrollThumbFrame.AbsoluteSize.x then break end
						Class:ScrollTo(Class.ScrollIndex + Class.VisibleSpace)
						wait()
					end
				else
					Class:ScrollTo(Class.ScrollIndex - Class.VisibleSpace)
					wait(0.2)
					while scrollEventID == current do
						if x > ScrollThumbFrame.AbsolutePosition.x then break end
						Class:ScrollTo(Class.ScrollIndex - Class.VisibleSpace)
						wait()
					end
				end
			end)
		else
			ScrollBarFrame.MouseButton1Down:connect(function(x,y)
				scrollEventID = tick()
				local current = scrollEventID
				local up_con
				up_con = MouseDrag.MouseButton1Up:connect(function()
					scrollEventID = tick()
					MouseDrag.Parent = nil
					ResetButtonColor(ScrollUpFrame)
					up_con:disconnect(); drag = nil
				end)
				MouseDrag.Parent = GetScreen(ScrollFrame)
				if y > ScrollThumbFrame.AbsolutePosition.y then
					Class:ScrollTo(Class.ScrollIndex + Class.VisibleSpace)
					wait(0.2)
					while scrollEventID == current do
						if y < ScrollThumbFrame.AbsolutePosition.y + ScrollThumbFrame.AbsoluteSize.y then break end
						Class:ScrollTo(Class.ScrollIndex + Class.VisibleSpace)
						wait()
					end
				else
					Class:ScrollTo(Class.ScrollIndex - Class.VisibleSpace)
					wait(0.2)
					while scrollEventID == current do
						if y > ScrollThumbFrame.AbsolutePosition.y then break end
						Class:ScrollTo(Class.ScrollIndex - Class.VisibleSpace)
						wait()
					end
				end
			end)
		end

		if horizontal then
			ScrollThumbFrame.MouseButton1Down:connect(function(x,y)
				scrollEventID = tick()
				local mouse_offset = x - ScrollThumbFrame.AbsolutePosition.x
				local drag_con
				local up_con
				drag_con = MouseDrag.MouseMoved:connect(function(x,y)
					local bar_abs_pos = ScrollBarFrame.AbsolutePosition.x
					local bar_drag = ScrollBarFrame.AbsoluteSize.x - ScrollThumbFrame.AbsoluteSize.x
					local bar_abs_one = bar_abs_pos + bar_drag
					x = x - mouse_offset
					x = x < bar_abs_pos and bar_abs_pos or x > bar_abs_one and bar_abs_one or x
					x = x - bar_abs_pos
					Class:SetScrollPercent(x/(bar_drag))
				end)
				up_con = MouseDrag.MouseButton1Up:connect(function()
					scrollEventID = tick()
					MouseDrag.Parent = nil
					ResetButtonColor(ScrollThumbFrame)
					drag_con:disconnect(); drag_con = nil
					up_con:disconnect(); drag = nil
				end)
				MouseDrag.Parent = GetScreen(ScrollFrame)
			end)
		else
			ScrollThumbFrame.MouseButton1Down:connect(function(x,y)
				scrollEventID = tick()
				local mouse_offset = y - ScrollThumbFrame.AbsolutePosition.y
				local drag_con
				local up_con
				drag_con = MouseDrag.MouseMoved:connect(function(x,y)
					local bar_abs_pos = ScrollBarFrame.AbsolutePosition.y
					local bar_drag = ScrollBarFrame.AbsoluteSize.y - ScrollThumbFrame.AbsoluteSize.y
					local bar_abs_one = bar_abs_pos + bar_drag
					y = y - mouse_offset
					y = y < bar_abs_pos and bar_abs_pos or y > bar_abs_one and bar_abs_one or y
					y = y - bar_abs_pos
					Class:SetScrollPercent(y/(bar_drag))
				end)
				up_con = MouseDrag.MouseButton1Up:connect(function()
					scrollEventID = tick()
					MouseDrag.Parent = nil
					ResetButtonColor(ScrollThumbFrame)
					drag_con:disconnect(); drag_con = nil
					up_con:disconnect(); drag = nil
				end)
				MouseDrag.Parent = GetScreen(ScrollFrame)
			end)
		end

		function Class:Destroy()
			ScrollFrame:Destroy()
			MouseDrag:Destroy()
			for k in pairs(Class) do
				Class[k] = nil
			end
			setmetatable(Class,nil)
		end

		Update()

		return Class
	end
end

----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
---- Explorer panel

local explorerPanel = script.Parent
Create(explorerPanel,{
	BackgroundColor3 = GuiColor.Field;
	BorderColor3 = GuiColor.Border;
	Active = true;
})

local listFrame = Create('Frame',{
	Name = "List";
	BackgroundTransparency = 1;
	ClipsDescendants = true;
	Position = UDim2.new(0,0,0,HEADER_SIZE);
	Size = UDim2.new(1,-GUI_SIZE,1,-HEADER_SIZE);
	Parent = explorerPanel;
})

local scrollBar = ScrollBar(false)
scrollBar.PageIncrement = 1
Create(scrollBar.GUI,{
	Position = UDim2.new(1,-GUI_SIZE,0,HEADER_SIZE);
	Size = UDim2.new(0,GUI_SIZE,1,-HEADER_SIZE);
	Parent = explorerPanel;
})

local scrollBarH = ScrollBar(true)
scrollBarH.PageIncrement = GUI_SIZE
Create(scrollBarH.GUI,{
	Position = UDim2.new(0,0,1,-GUI_SIZE);
	Size = UDim2.new(1,-GUI_SIZE,0,GUI_SIZE);
	Visible = false;
	Parent = explorerPanel;
})

local headerFrame = Create('Frame',{
	Name = "Header";
	BackgroundColor3 = GuiColor.Background;
	BorderColor3 = GuiColor.Border;
	Position = UDim2.new(0,0,0,0);
	Size = UDim2.new(1,0,0,HEADER_SIZE);
	Parent = explorerPanel;
	Create('TextLabel',{
		Text = "Explorer";
		BackgroundTransparency = 1;
		TextColor3 = GuiColor.Text;
		TextXAlignment = 'Left';
		Font = FONT;
		FontSize = FONT_SIZE;
		Position = UDim2.new(0,4,0,0);
		Size = UDim2.new(1,-4,1,0);
	});
})

SetZIndexOnChanged(explorerPanel)

local getTextWidth do
	local text = Create('TextLabel',{
		Name = "TextWidth";
		TextXAlignment = 'Left';
		TextYAlignment = 'Center';
		Font = FONT;
		FontSize = FONT_SIZE;
		Text = "";
		Position = UDim2.new(0,0,0,0);
		Size = UDim2.new(1,0,1,0);
		Visible = false;
		Parent = explorerPanel;
	})
	function getTextWidth(s)
		text.Text = s
		return text.TextBounds.x
	end
end

-- Holds the game tree converted to a list.
local TreeList = {}
-- Matches objects to their tree node representation.
local NodeLookup = {}

local nodeWidth = 0

local updateList,rawUpdateList,updateScroll,rawUpdateSize do
	local function r(t)
		for i = 1,#t do
			TreeList[#TreeList+1] = t[i]

			local w = (t[i].Depth)*(2+ENTRY_PADDING+GUI_SIZE) + 2 + ENTRY_SIZE + 4 + getTextWidth(t[i].Object.Name) + 4
			if w > nodeWidth then
				nodeWidth = w
			end
			if t[i].Expanded then
				r(t[i])
			end
		end
	end

	function rawUpdateSize()
		scrollBarH.TotalSpace = nodeWidth
		scrollBarH.VisibleSpace = listFrame.AbsoluteSize.x
		scrollBarH:Update()
		local visible = scrollBarH:CanScrollDown() or scrollBarH:CanScrollUp()
		scrollBarH.GUI.Visible = visible

		listFrame.Size = UDim2.new(1,-GUI_SIZE,1,-GUI_SIZE*(visible and 1 or 0) - HEADER_SIZE)

		scrollBar.VisibleSpace = math.ceil(listFrame.AbsoluteSize.y/ENTRY_BOUND)
		scrollBar.GUI.Size = UDim2.new(0,GUI_SIZE,1,-GUI_SIZE*(visible and 1 or 0) - HEADER_SIZE)

		scrollBar.TotalSpace = #TreeList+1
		scrollBar:Update()
	end

	function rawUpdateList()
		-- Clear then repopulate the entire list. It appears to be fast enough.
		TreeList = {}
		nodeWidth = 0
		r(NodeLookup[Game])
		rawUpdateSize()
	end

	-- Adding or removing large models will cause many updates to occur. We
	-- can reduce the number of updates by creating a delay, then dropping any
	-- updates that occur during the delay.
	local updatingList = false
	function updateList()
		if updatingList then return end
		updatingList = true
		wait(0.25)
		updatingList = false
		rawUpdateList()
	end

	local updatingScroll = false
	function updateScroll()
		if updatingScroll then return end
		updatingScroll = true
		wait(0.25)
		updatingScroll = false
		scrollBar:Update()
	end
end

local Selection do
	local bindGetSelection = script.Parent:FindFirstChild("GetSelection")
	if not bindGetSelection then
		bindGetSelection = Create('BindableFunction',{Name = "GetSelection"})
		bindGetSelection.Parent = script.Parent
	end

	local bindSetSelection = script.Parent:FindFirstChild("SetSelection")
	if not bindSetSelection then
		bindSetSelection = Create('BindableFunction',{Name = "SetSelection"})
		bindSetSelection.Parent = script.Parent
	end

	local bindSelectionChanged = script.Parent:FindFirstChild("SelectionChanged")
	if not bindSelectionChanged then
		bindSelectionChanged = Create('BindableEvent',{Name = "SelectionChanged"})
		bindSelectionChanged.Parent = script.Parent
	end

	local SelectionList = {}
	local SelectionSet = {}
	Selection = {
		Selected = SelectionSet;
		List = SelectionList;
	}

	local function addObject(object)
		-- list update
		local lupdate = false
		-- scroll update
		local supdate = false

		if not SelectionSet[object] then
			local node = NodeLookup[object]
			if node then
				table.insert(SelectionList,object)
				SelectionSet[object] = true
				node.Selected = true

				-- expand all ancestors so that selected node becomes visible
				node = node.Parent
				while node do
					if not node.Expanded then
						node.Expanded = true
						lupdate = true
					end
					node = node.Parent
				end
				supdate = true
			end
		end
		return lupdate,supdate
	end

	function Selection:Set(objects)
		local lupdate = false
		local supdate = false

		if #SelectionList > 0 then
			for i = 1,#SelectionList do
				local object = SelectionList[i]
				local node = NodeLookup[object]
				if node then
					node.Selected = false
					SelectionSet[object] = nil
				end
			end

			SelectionList = {}
			Selection.List = SelectionList
			supdate = true
		end

		for i = 1,#objects do
			local l,s = addObject(objects[i])
			lupdate = l or lupdate
			supdate = s or supdate
		end

		if lupdate then
			rawUpdateList()
			supdate = true
		elseif supdate then
			scrollBar:Update()
		end

		if supdate then
			bindSelectionChanged:Fire()
		end
	end

	function Selection:Add(object)
		local l,s = addObject(object)
		if l then
			rawUpdateList()
			bindSelectionChanged:Fire()
		elseif s then
			scrollBar:Update()
			bindSelectionChanged:Fire()
		end
	end

	function Selection:Remove(object,noupdate)
		if SelectionSet[object] then
			local node = NodeLookup[object]
			if node then
				node.Selected = false
				SelectionSet[object] = nil
				for i = 1,#SelectionList do
					if SelectionList[i] == object then
						table.remove(SelectionList,i)
						break
					end
				end

				if not noupdate then
					scrollBar:Update()
				end
				bindSelectionChanged:Fire()
			end
		end
	end

	function Selection:Get()
		local list = {}
		for i = 1,#SelectionList do
			list[i] = SelectionList[i]
		end
		return list
	end

	bindSetSelection.OnInvoke = function(...)
		Selection:Set(...)
	end

	bindGetSelection.OnInvoke = function()
		return Selection:Get()
	end
end

local function cancelReparentDrag()end
local function cancelSelectDrag()end
do
	local listEntries = {}
	local nameConnLookup = {}

	local mouseDrag = Create('ImageButton',{
		Name = "MouseDrag";
		Position = UDim2.new(-0.25,0,-0.25,0);
		Size = UDim2.new(1.5,0,1.5,0);
		Transparency = 1;
		AutoButtonColor = false;
		Active = true;
		ZIndex = 10;
	})
	local function dragSelect(last,add,button)
		local connDrag
		local conUp

		conDrag = mouseDrag.MouseMoved:connect(function(x,y)
			local pos = Vector2.new(x,y) - listFrame.AbsolutePosition
			local size = listFrame.AbsoluteSize
			if pos.x < 0 or pos.x > size.x or pos.y < 0 or pos.y > size.y then return end

			local i = math.ceil(pos.y/ENTRY_BOUND) + scrollBar.ScrollIndex
			-- Mouse may have made a large step, so interpolate between the
			-- last index and the current.
			for n = i<last and i or last, i>last and i or last do
				local node = TreeList[n]
				if node then
					if add then
						Selection:Add(node.Object)
					else
						Selection:Remove(node.Object)
					end
				end
			end
			last = i
		end)

		function cancelSelectDrag()
			mouseDrag.Parent = nil
			conDrag:disconnect()
			conUp:disconnect()
			function cancelSelectDrag()end
		end

		conUp = mouseDrag[button]:connect(cancelSelectDrag)

		mouseDrag.Parent = GetScreen(listFrame)
	end

	local function dragReparent(object,dragGhost,clickPos,ghostOffset)
		local connDrag
		local conUp
		local conUp2

		local parentIndex = nil
		local dragged = false

		local parentHighlight = Create('Frame',{
			Transparency = 1;
			Visible = false;
			Create('Frame',{
				BorderSizePixel = 0;
				BackgroundColor3 = Color3.new(0,0,0);
				BackgroundTransparency = 0.1;
				Position = UDim2.new(0,0,0,0);
				Size = UDim2.new(1,0,0,1);
			});
			Create('Frame',{
				BorderSizePixel = 0;
				BackgroundColor3 = Color3.new(0,0,0);
				BackgroundTransparency = 0.1;
				Position = UDim2.new(1,0,0,0);
				Size = UDim2.new(0,1,1,0);
			});
			Create('Frame',{
				BorderSizePixel = 0;
				BackgroundColor3 = Color3.new(0,0,0);
				BackgroundTransparency = 0.1;
				Position = UDim2.new(0,0,1,0);
				Size = UDim2.new(1,0,0,1);
			});
			Create('Frame',{
				BorderSizePixel = 0;
				BackgroundColor3 = Color3.new(0,0,0);
				BackgroundTransparency = 0.1;
				Position = UDim2.new(0,0,0,0);
				Size = UDim2.new(0,1,1,0);
			});
		})
		SetZIndex(parentHighlight,9)

		conDrag = mouseDrag.MouseMoved:connect(function(x,y)
			local dragPos = Vector2.new(x,y)
			if dragged then
				local pos = dragPos - listFrame.AbsolutePosition
				local size = listFrame.AbsoluteSize

				parentIndex = nil
				parentHighlight.Visible = false
				if pos.x >= 0 and pos.x <= size.x and pos.y >= 0 and pos.y <= size.y then
					local i = math.ceil(pos.y/ENTRY_BOUND)
					local node = TreeList[i + scrollBar.ScrollIndex]
					if node and node.Object ~= object and not object:IsAncestorOf(node.Object) then
						parentIndex = i
						local entry = listEntries[i]
						if entry then
							parentHighlight.Visible = true
							parentHighlight.Position = UDim2.new(0,1,0,entry.AbsolutePosition.y-listFrame.AbsolutePosition.y)
							parentHighlight.Size = UDim2.new(0,size.x-4,0,entry.AbsoluteSize.y)
						end
					end
				end

				dragGhost.Position = UDim2.new(0,dragPos.x+ghostOffset.x,0,dragPos.y+ghostOffset.y)
			elseif (clickPos-dragPos).magnitude > 8 then
				dragged = true
				SetZIndex(dragGhost,9)
				dragGhost.IndentFrame.Transparency = 0.25
				dragGhost.IndentFrame.EntryText.TextColor3 = GuiColor.TextSelected
				dragGhost.Position = UDim2.new(0,dragPos.x+ghostOffset.x,0,dragPos.y+ghostOffset.y)
				dragGhost.Parent = GetScreen(listFrame)
				parentHighlight.Parent = listFrame
			end
		end)

		function cancelReparentDrag()
			mouseDrag.Parent = nil
			conDrag:disconnect()
			conUp:disconnect()
			conUp2:disconnect()
			dragGhost:Destroy()
			parentHighlight:Destroy()
			function cancelReparentDrag()end
		end

		local wasSelected = Selection.Selected[object]
		if not wasSelected and Option.Selectable then
			Selection:Set({object})
		end

		conUp = mouseDrag.MouseButton1Up:connect(function()
			cancelReparentDrag()
			if dragged then
				if parentIndex then
					local parentNode = TreeList[parentIndex + scrollBar.ScrollIndex]
					if parentNode then
						parentNode.Expanded = true

						local parentObj = parentNode.Object
						local function parent(a,b)
							a.Parent = b
						end
						if Option.Selectable then
							local list = Selection.List
							for i = 1,#list do
								pcall(parent,list[i],parentObj)
							end
						else
							pcall(parent,object,parentObj)
						end
					end
				end
			else
				-- do selection click
				if wasSelected and Option.Selectable then
					Selection:Set({})
				end
			end
		end)
		conUp2 = mouseDrag.MouseButton2Down:connect(function()
			cancelReparentDrag()
		end)

		mouseDrag.Parent = GetScreen(listFrame)
	end

	local entryTemplate = Create('ImageButton',{
		Name = "Entry";
		Transparency = 1;
		AutoButtonColor = false;
		Position = UDim2.new(0,0,0,0);
		Size = UDim2.new(1,0,0,ENTRY_SIZE);
		Create('Frame',{
			Name = "IndentFrame";
			BackgroundTransparency = 1;
			BackgroundColor3 = GuiColor.Selected;
			BorderColor3 = GuiColor.BorderSelected;
			Position = UDim2.new(0,0,0,0);
			Size = UDim2.new(1,0,1,0);
			Create(Icon('ImageButton',0),{
				Name = "Expand";
				AutoButtonColor = false;
				Position = UDim2.new(0,-GUI_SIZE,0.5,-GUI_SIZE/2);
				Size = UDim2.new(0,GUI_SIZE,0,GUI_SIZE);
			});
			Create(Icon(nil,0),{
				Name = "ExplorerIcon";
				Position = UDim2.new(0,2+ENTRY_PADDING,0.5,-GUI_SIZE/2);
				Size = UDim2.new(0,GUI_SIZE,0,GUI_SIZE);
			});
			Create('TextLabel',{
				Name = "EntryText";
				BackgroundTransparency = 1;
				TextColor3 = GuiColor.Text;
				TextXAlignment = 'Left';
				TextYAlignment = 'Center';
				Font = FONT;
				FontSize = FONT_SIZE;
				Text = "";
				Position = UDim2.new(0,2+ENTRY_SIZE+4,0,0);
				Size = UDim2.new(1,-2,1,0);
			});
		});
	})

	function scrollBar.UpdateCallback(self)
		for i = 1,self.VisibleSpace do
			local node = TreeList[i + self.ScrollIndex]
			if node then
				local entry = listEntries[i]
				if not entry then
					entry = Create(entryTemplate:Clone(),{
						Position = UDim2.new(0,2,0,ENTRY_BOUND*(i-1)+2);
						Size = UDim2.new(0,nodeWidth,0,ENTRY_SIZE);
						ZIndex = listFrame.ZIndex;
					})
					listEntries[i] = entry

					local expand = entry.IndentFrame.Expand
					expand.MouseEnter:connect(function()
						local node = TreeList[i + self.ScrollIndex]
						if #node > 0 then
							if node.Expanded then
								Icon(expand,NODE_EXPANDED_OVER)
							else
								Icon(expand,NODE_COLLAPSED_OVER)
							end
						end
					end)
					expand.MouseLeave:connect(function()
						local node = TreeList[i + self.ScrollIndex]
						if #node > 0 then
							if node.Expanded then
								Icon(expand,NODE_EXPANDED)
							else
								Icon(expand,NODE_COLLAPSED)
							end
						end
					end)
					expand.MouseButton1Down:connect(function()
						local node = TreeList[i + self.ScrollIndex]
						if #node > 0 then
							node.Expanded = not node.Expanded
							-- use raw update so the list updates instantly
							rawUpdateList()
						end
					end)

					entry.MouseButton1Down:connect(function(x,y)
						local node = TreeList[i + self.ScrollIndex]
						if Option.Modifiable then
							local pos = Vector2.new(x,y)
							dragReparent(node.Object,entry:Clone(),pos,entry.AbsolutePosition-pos)
						elseif Option.Selectable then
							if Selection.Selected[node.Object] then
								Selection:Set({})
							else
								Selection:Set({node.Object})
							end
							dragSelect(i+self.ScrollIndex,true,'MouseButton1Up')
						end
					end)

					entry.MouseButton2Down:connect(function()
						if not Option.Selectable then return end

						local node = TreeList[i + self.ScrollIndex]
						if Selection.Selected[node.Object] then
							Selection:Remove(node.Object)
							dragSelect(i+self.ScrollIndex,false,'MouseButton2Up')
						else
							Selection:Add(node.Object)
							dragSelect(i+self.ScrollIndex,true,'MouseButton2Up')
						end
					end)

					entry.Parent = listFrame
				end

				entry.Visible = true

				local object = node.Object

				-- update expand icon
				if #node == 0 then
					entry.IndentFrame.Expand.Visible = false
				elseif node.Expanded then
					Icon(entry.IndentFrame.Expand,NODE_EXPANDED)
					entry.IndentFrame.Expand.Visible = true
				else
					Icon(entry.IndentFrame.Expand,NODE_COLLAPSED)
					entry.IndentFrame.Expand.Visible = true
				end

				-- update explorer icon
				Icon(entry.IndentFrame.ExplorerIcon,ExplorerIndex[object.ClassName] or 0)

				-- update indentation
				local w = (node.Depth)*(2+ENTRY_PADDING+GUI_SIZE)
				entry.IndentFrame.Position = UDim2.new(0,w,0,0)
				entry.IndentFrame.Size = UDim2.new(1,-w,1,0)

				-- update name change detection
				if nameConnLookup[entry] then
					nameConnLookup[entry]:disconnect()
				end
				local text = entry.IndentFrame.EntryText
				text.Text = object.Name
				nameConnLookup[entry] = node.Object.Changed:connect(function(p)
					if p == 'Name' then
						text.Text = object.Name
					end
				end)

				-- update selection
				entry.IndentFrame.Transparency = node.Selected and 0 or 1
				text.TextColor3 = GuiColor[node.Selected and 'TextSelected' or 'Text']

				entry.Size = UDim2.new(0,nodeWidth,0,ENTRY_SIZE)
			elseif listEntries[i] then
				listEntries[i].Visible = false
			end
		end
		for i = self.VisibleSpace+1,self.TotalSpace do
			local entry = listEntries[i]
			if entry then
				listEntries[i] = nil
				entry:Destroy()
			end
		end
	end

	function scrollBarH.UpdateCallback(self)
		for i = 1,scrollBar.VisibleSpace do
			local node = TreeList[i + scrollBar.ScrollIndex]
			if node then
				local entry = listEntries[i]
				if entry then
					entry.Position = UDim2.new(0,2 - scrollBarH.ScrollIndex,0,ENTRY_BOUND*(i-1)+2)
				end
			end
		end
	end

	Connect(listFrame.Changed,function(p)
		if p == 'AbsoluteSize' then
			rawUpdateSize()
		end
	end)

	local wheelAmount = 6
	explorerPanel.MouseWheelForward:connect(function()
		if scrollBar.VisibleSpace - 1 > wheelAmount then
			scrollBar:ScrollTo(scrollBar.ScrollIndex - wheelAmount)
		else
			scrollBar:ScrollTo(scrollBar.ScrollIndex - scrollBar.VisibleSpace)
		end
	end)
	explorerPanel.MouseWheelBackward:connect(function()
		if scrollBar.VisibleSpace - 1 > wheelAmount then
			scrollBar:ScrollTo(scrollBar.ScrollIndex + wheelAmount)
		else
			scrollBar:ScrollTo(scrollBar.ScrollIndex + scrollBar.VisibleSpace)
		end
	end)
end

----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
---- Object detection

-- Inserts `v` into `t` at `i`. Also sets `Index` field in `v`.
local function insert(t,i,v)
	for n = #t,i,-1 do
		local v = t[n]
		v.Index = n+1
		t[n+1] = v
	end
	v.Index = i
	t[i] = v
end

-- Removes `i` from `t`. Also sets `Index` field in removed value.
local function remove(t,i)
	local v = t[i]
	for n = i+1,#t do
		local v = t[n]
		v.Index = n-1
		t[n-1] = v
	end
	t[#t] = nil
	v.Index = 0
	return v
end

-- Returns how deep `o` is in the tree.
local function depth(o)
	local d = -1
	while o do
		o = o.Parent
		d = d + 1
	end
	return d
end


local connLookup = {}

-- Returns whether a node would be present in the tree list
local function nodeIsVisible(node)
	local visible = true
	node = node.Parent
	while node and visible do
		visible = visible and node.Expanded
		node = node.Parent
	end
	return visible
end

-- Removes an object's tree node. Called when the object stops existing in the
-- game tree.
local function removeObject(object)
	local objectNode = NodeLookup[object]
	if not objectNode then
		return
	end

	local visible = nodeIsVisible(objectNode)

	Selection:Remove(object,true)

	local parent = objectNode.Parent
	remove(parent,objectNode.Index)
	NodeLookup[object] = nil
	connLookup[object]:disconnect()
	connLookup[object] = nil

	if visible then
		updateList()
	elseif nodeIsVisible(parent) then
		updateScroll()
	end
end

-- Moves a tree node to a new parent. Called when an existing object's parent
-- changes.
local function moveObject(object,parent)
	local objectNode = NodeLookup[object]
	if not objectNode then
		return
	end

	local parentNode = NodeLookup[parent]
	if not parentNode then
		return
	end

	local visible = nodeIsVisible(objectNode)

	remove(objectNode.Parent,objectNode.Index)
	objectNode.Parent = parentNode

	objectNode.Depth = depth(object)
	local function r(node,d)
		for i = 1,#node do
			node[i].Depth = d
			r(node[i],d+1)
		end
	end
	r(objectNode,objectNode.Depth+1)

	insert(parentNode,#parentNode+1,objectNode)

	if visible or nodeIsVisible(objectNode) then
		updateList()
	elseif nodeIsVisible(objectNode.Parent) then
		updateScroll()
	end
end

-- ScriptContext['/Libraries/LibraryRegistration/LibraryRegistration']
-- This RobloxLocked object lets me index its properties for some reason

local function check(object)
	return object.AncestryChanged
end

-- Creates a new tree node from an object. Called when an object starts
-- existing in the game tree.
local function addObject(object,noupdate)
	if script then
		-- protect against naughty RobloxLocked objects
		local s = pcall(check,object)
		if not s then
			return
		end
	end

	local parentNode = NodeLookup[object.Parent]
	if not parentNode then
		return
	end

	local objectNode = {
		Object = object;
		Parent = parentNode;
		Index = 0;
		Expanded = false;
		Selected = false;
		Depth = depth(object);
	}

	connLookup[object] = Connect(object.AncestryChanged,function(c,p)
		if c == object then
			if p == nil then
				removeObject(c)
			else
				moveObject(c,p)
			end
		end
	end)

	NodeLookup[object] = objectNode
	insert(parentNode,#parentNode+1,objectNode)

	if not noupdate then
		if nodeIsVisible(objectNode) then
			updateList()
		elseif nodeIsVisible(objectNode.Parent) then
			updateScroll()
		end
	end
end

do
	NodeLookup[Game] = {
		Object = Game;
		Parent = nil;
		Index = 0;
		Expanded = true;
	}

	Connect(Game.DescendantAdded,addObject)
	Connect(Game.DescendantRemoving,removeObject)

	local function get(o)
		return o:GetChildren()
	end

	local function r(o)
		local s,children = pcall(get,o)
		if s then
			for i = 1,#children do
				addObject(children[i],true)
				r(children[i])
			end
		end
	end

	r(Game)

	scrollBar.VisibleSpace = math.ceil(listFrame.AbsoluteSize.y/ENTRY_BOUND)
	updateList()
end

----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
---- Actions

local actionButtons do
	actionButtons = {}

	local totalActions = (4) + 1
	local currentActions = totalActions
	local function makeButton(icon,over,name)
		local button = Create(Icon('ImageButton',icon),{
			Name = name .. "Button";
			Visible = Option.Modifiable and Option.Selectable;
			Position = UDim2.new(1,-(GUI_SIZE+2)*currentActions+2,0.5,-GUI_SIZE/2);
			Size = UDim2.new(0,GUI_SIZE,0,GUI_SIZE);
			Parent = headerFrame;
		})

		local tipText = Create('TextLabel',{
			Name = name .. "Text";
			Text = name;
			Visible = false;
			BackgroundTransparency = 1;
			TextXAlignment = 'Right';
			Font = FONT;
			FontSize = FONT_SIZE;
			Position = UDim2.new(0,0,0,0);
			Size = UDim2.new(1,-(GUI_SIZE+2)*totalActions,1,0);
			Parent = headerFrame;
		})


		button.MouseEnter:connect(function()
			Icon(button,over)
			tipText.Visible = true
		end)
		button.MouseLeave:connect(function()
			Icon(button,icon)
			tipText.Visible = false
		end)

		currentActions = currentActions - 1
		actionButtons[#actionButtons+1] = button
		return button
	end

	local clipboard = {}
	local function delete(o)
		o.Parent = nil
	end

	-- CUT
	makeButton(ACTION_CUT,ACTION_CUT_OVER,"Cut").MouseButton1Click:connect(function()
		if not Option.Modifiable then return end
		clipboard = {}
		local list = Selection.List
		local cut = {}
		for i = 1,#list do
			local obj = list[i]:Clone()
			if obj then
				table.insert(clipboard,obj)
				table.insert(cut,list[i])
			end
		end
		for i = 1,#cut do
			pcall(delete,cut[i])
		end
	end)

	-- COPY
	makeButton(ACTION_COPY,ACTION_COPY_OVER,"Copy").MouseButton1Click:connect(function()
		if not Option.Modifiable then return end
		clipboard = {}
		local list = Selection.List
		for i = 1,#list do
			table.insert(clipboard,list[i]:Clone())
		end
	end)

	-- PASTE
	makeButton(ACTION_PASTE,ACTION_PASTE_OVER,"Paste").MouseButton1Click:connect(function()
		if not Option.Modifiable then return end
		local parent = Selection.List[1] or Workspace
		for i = 1,#clipboard do
			clipboard[i]:Clone().Parent = parent
		end
	end)

	-- DELETE
	makeButton(ACTION_DELETE,ACTION_DELETE_OVER,"Delete").MouseButton1Click:connect(function()
		if not Option.Modifiable then return end
		local list = Selection:Get()
		for i = 1,#list do
			pcall(delete,list[i])
		end
		Selection:Set({})
	end)

	-- SORT
	-- local actionSort = makeButton(ACTION_SORT,ACTION_SORT_OVER,"Sort")
end

----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
----------------------------------------------------------------
---- Option Bindables

do
	local optionCallback = {
		Modifiable = function(value)
			for i = 1,#actionButtons do
				actionButtons[i].Visible = value and Option.Selectable
			end
			cancelReparentDrag()
		end;
		Selectable = function(value)
			for i = 1,#actionButtons do
				actionButtons[i].Visible = value and Option.Modifiable
			end
			cancelSelectDrag()
			Selection:Set({})
		end;
	}

	local bindSetOption = script.Parent:FindFirstChild("SetOption")
	if not bindSetOption then
		bindSetOption = Create('BindableFunction',{Name = "SetOption"})
		bindSetOption.Parent = script.Parent
	end

	bindSetOption.OnInvoke = function(optionName,value)
		if optionCallback[optionName] then
			Option[optionName] = value
			optionCallback[optionName](value)
		end
	end

	local bindGetOption = script.Parent:FindFirstChild("GetOption")
	if not bindGetOption then
		bindGetOption = Create('BindableFunction',{Name = "GetOption"})
		bindGetOption.Parent = script.Parent
	end

	bindGetOption.OnInvoke = function(optionName)
		if optionName then
			return Option[optionName]
		else
			local options = {}
			for k,v in pairs(Option) do
				options[k] = v
			end
			return options
		end
	end
end