java.lang.NullPointerException
	at com.android.ide.eclipse.adt.internal.project.SupportLibraryHelper.getTagFor(SupportLibraryHelper.java:87)
	at com.android.ide.eclipse.adt.internal.editors.layout.gre.NodeProxy.insertOrAppend(NodeProxy.java:273)
	at com.android.ide.eclipse.adt.internal.editors.layout.gre.NodeProxy.insertChildAt(NodeProxy.java:254)
	at com.android.ide.common.layout.RelativeLayoutRule$1.handle(RelativeLayoutRule.java:210)
	at com.android.ide.eclipse.adt.internal.editors.layout.gre.NodeProxy$1.run(NodeProxy.java:233)
	at com.android.ide.eclipse.adt.internal.editors.AndroidXmlEditor.wrapEditXmlModel(AndroidXmlEditor.java:1049)
	at com.android.ide.eclipse.adt.internal.editors.AndroidXmlEditor.wrapUndoEditXmlModel(AndroidXmlEditor.java:1190)
	at com.android.ide.eclipse.adt.internal.editors.layout.gre.NodeProxy.editXml(NodeProxy.java:224)
	at com.android.ide.common.layout.RelativeLayoutRule.onDropped(RelativeLayoutRule.java:191)
	at com.android.ide.eclipse.adt.internal.editors.layout.gre.RulesEngine.callOnDropped(RulesEngine.java:367)
	at com.android.ide.eclipse.adt.internal.editors.layout.gle2.MoveGesture$2.run(MoveGesture.java:400)
	at com.android.ide.eclipse.adt.internal.editors.AndroidXmlEditor.wrapEditXmlModel(AndroidXmlEditor.java:1049)
	at com.android.ide.eclipse.adt.internal.editors.AndroidXmlEditor.wrapUndoEditXmlModel(AndroidXmlEditor.java:1190)
	at com.android.ide.eclipse.adt.internal.editors.layout.gle2.MoveGesture.drop(MoveGesture.java:396)
	at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GestureManager$CanvasDropListener.drop(GestureManager.java:679)
	at org.eclipse.swt.dnd.DNDListener.handleEvent(DNDListener.java:90)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1077)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1062)
	at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:774)
	at org.eclipse.swt.dnd.DropTarget.Drop(DropTarget.java:456)
	at org.eclipse.swt.dnd.DropTarget$3.method6(DropTarget.java:258)
	at org.eclipse.swt.internal.ole.win32.COMObject.callback6(COMObject.java:119)
	at org.eclipse.swt.internal.ole.win32.COM.DoDragDrop(Native Method)
	at org.eclipse.swt.dnd.DragSource.drag(DragSource.java:363)
	at org.eclipse.swt.dnd.DragSource.access$0(DragSource.java:289)
	at org.eclipse.swt.dnd.DragSource$1.handleEvent(DragSource.java:172)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4169)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3758)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1022)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:916)
	at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:86)
	at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:585)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:540)
	at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
	at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:124)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:353)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:180)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:629)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1438)