#include <ButtonConstants.au3>
#include <GUIConstantsEx.au3>
#include <WindowsConstants.au3>

Opt("GUIOnEventMode", 1)

$gui1 = GUICreate("GUI-1", 259, 46)
GUISetOnEvent($GUI_EVENT_CLOSE, "_exit")
$Button1 = GUICtrlCreateButton("zu GUI-1", 8, 8, 75, 25, $WS_GROUP)
GUICtrlSetState(-1, $GUI_DISABLE)
$Button2 = GUICtrlCreateButton("zu GUI-2", 88, 8, 75, 25, $WS_GROUP)
GUICtrlSetOnEvent(-1, "_show2")
$Button3 = GUICtrlCreateButton("zu GUI-3", 168, 8, 75, 25, $WS_GROUP)
GUICtrlSetOnEvent(-1, "_show3")
GUISetState(@SW_SHOW)

$gui2 = GUICreate("GUI-2", 259, 46)
GUISetOnEvent($GUI_EVENT_CLOSE, "_exit")
$Button1 = GUICtrlCreateButton("zu GUI-1", 8, 8, 75, 25, $WS_GROUP)
GUICtrlSetOnEvent(-1, "_show1")
$Button2 = GUICtrlCreateButton("zu GUI-2", 88, 8, 75, 25, $WS_GROUP)
GUICtrlSetState(-1, $GUI_DISABLE)
$Button3 = GUICtrlCreateButton("zu GUI-3", 168, 8, 75, 25, $WS_GROUP)
GUICtrlSetOnEvent(-1, "_show3")
GUISetState(@SW_HIDE)

$gui3 = GUICreate("GUI-3", 259, 46)
GUISetOnEvent($GUI_EVENT_CLOSE, "_exit")
$Button1 = GUICtrlCreateButton("zu GUI-1", 8, 8, 75, 25, $WS_GROUP)
GUICtrlSetOnEvent(-1, "_show1")
$Button2 = GUICtrlCreateButton("zu GUI-2", 88, 8, 75, 25, $WS_GROUP)
GUICtrlSetOnEvent(-1, "_show2")
$Button3 = GUICtrlCreateButton("zu GUI-3", 168, 8, 75, 25, $WS_GROUP)
GUICtrlSetState(-1, $GUI_DISABLE)
GUISetState(@SW_HIDE)

While 1
    Sleep(100)
WEnd

Func _show1()
    GUISetState(@SW_HIDE, $gui2)
    GUISetState(@SW_HIDE, $gui3)
    GUISetState(@SW_SHOW, $gui1)
EndFunc   ;==>_show1

Func _show2()
    GUISetState(@SW_HIDE, $gui1)
    GUISetState(@SW_HIDE, $gui3)
    GUISetState(@SW_SHOW, $gui2)
EndFunc   ;==>_show2

Func _show3()
    GUISetState(@SW_HIDE, $gui1)
    GUISetState(@SW_HIDE, $gui2)
    GUISetState(@SW_SHOW, $gui3)
EndFunc   ;==>_show3

Func _exit()
    Exit
EndFunc   ;==>_exit