Bug 319961 Reset perspective fails with parts moved into the editor area
1. Start a fresh e4 workbench 2. Move the Javadoc view into the editor area 3. Reset the perspective 4. Open the Javadoc view Result: The Javadoc view is opened in the editor area. In the bottom stack there still is a tab for the Javadoc view; this tab can be clicked, but it will activate the view in the editor area. The toolbar, however, is shown in the bottom stack.
bundles/org.eclipse.e4.ui.workbench.addons.swt/src/org/eclipse/e4/ui/workbench/addons/dndaddon/StackDropAgent.java
@Override
	public boolean canDrop(MUIElement dragElement, CursorInfo info) {
		if (info.curElement == dragElement.getParent()) {
			if (info.curElement != null && info.curElement == dragElement.getParent()) {
				CTabFolder ctf = (CTabFolder) dragElement.getParent().getWidget();
				return ctf.getItemCount() > 1;
			}
		}
		if (dragElement instanceof MPart && info.curElement instanceof MPartStack)
			return true;
		return false;
	}
	@Override
	public boolean drop(MUIElement dragElement, CursorInfo info) {
		MPartStack dropStack = (MPartStack) info.curElement;