Bug 303801 IAE thrown when moving a part from one stack to another
1. Start the photo demo. 2. Move the 'Thumbnails' view to the stack of the 'Location' view. 3. An IAE is thrown. java.lang.IllegalArgumentException: Widget has the wrong parent at org.eclipse.swt.SWT.error(SWT.java:4064) at org.eclipse.swt.SWT.error(SWT.java:3998) at org.eclipse.swt.SWT.error(SWT.java:3969) at org.eclipse.swt.custom.CTabItem.setControl(CTabItem.java:283) at org.eclipse.e4.workbench.ui.renderers.swt.StackRenderer.createTab(StackRenderer.java:286) at org.eclipse.e4.workbench.ui.renderers.swt.StackRenderer.childRendered(StackRenderer.java:313) at org.eclipse.e4.ui.workbench.swt.internal.PartRenderingEngine$2.handleEvent(PartRenderingEngine.java:139) at org.eclipse.e4.ui.services.internal.events.UIEventHandler.handleEvent(UIEventHandler.java:41) at org.eclipse.equinox.internal.event.EventHandlerWrapper.handleEvent(EventHandlerWrapper.java:188) at org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(EventHandlerTracker.java:198) at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:227) at org.eclipse.osgi.framework.eventmgr.ListenerQueue.dispatchEventSynchronous(ListenerQueue.java:149) at org.eclipse.equinox.internal.event.EventAdminImpl.dispatchEvent(EventAdminImpl.java:139) at org.eclipse.equinox.internal.event.EventAdminImpl.sendEvent(EventAdminImpl.java:78) at org.eclipse.equinox.internal.event.EventComponent.sendEvent(EventComponent.java:39) at org.eclipse.e4.ui.services.internal.events.EventBroker.send(EventBroker.java:73) at org.eclipse.e4.workbench.ui.internal.UIEventPublisher.notifyChanged(UIEventPublisher.java:58) at org.eclipse.emf.common.notify.impl.BasicNotifierImpl.eNotify(BasicNotifierImpl.java:280) at org.eclipse.emf.common.notify.impl.NotificationImpl.dispatch(NotificationImpl.java:1033) at org.eclipse.emf.common.notify.impl.NotificationImpl.dispatch(NotificationImpl.java:1038) at org.eclipse.emf.common.notify.impl.NotifyingListImpl.addUnique(NotifyingListImpl.java:305) at org.eclipse.emf.common.util.AbstractEList.add(AbstractEList.java:307) at org.eclipse.e4.workbench.ui.renderers.swt.dnd.DragHost.drop(DragHost.java:119) at org.eclipse.e4.workbench.ui.renderers.swt.dnd.DnDManager.endDrag(DnDManager.java:224) at org.eclipse.e4.workbench.ui.renderers.swt.dnd.DnDManager$2.handleEvent(DnDManager.java:73) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/workbench/ui/renderers/swt/dnd/DnDManager.java
protected Point downPos;
	protected CursorInfo downInfo;
	private DragHost dragHost;
	
	private MUIElement curOverlayElement;
	private Display display;
	Listener keyListener = new Listener() {
		public void handleEvent(Event event) {
			if (event.character == SWT.ESC && dragHost != null) {
				cancelDrag();
			}
		}
	};
	Listener mouseButtonListener = new Listener() {
		public void handleEvent(Event event) {
			if (event.button != 1) {
				downPos = null;
				return;
			}
			CursorInfo info = dndUtil.getCursorInfo();
			if (event.type == SWT.MouseDown && dragHost == null
					&& !(info.curElement instanceof MGenericTile<?>)
					&& !(info.curElement instanceof MPart)) {
				downPos = new Point(event.x, event.y);
				downInfo = info;
			} else if (event.type == SWT.MouseUp) {
				downPos = null;
				downInfo = null;
				if (dragHost != null) {
					CursorInfo dropInfo = getDropInfo();