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
public Rectangle getRectangle(MUIElement dragElement, CursorInfo info) {
		CTabFolder ctf = (CTabFolder) info.curElement.getWidget();
		if (info.itemElement != null) {
			if (info.curElement.getWidget() instanceof CTabFolder) {
				for (CTabItem cti : ctf.getItems()) {
					if (cti.getData(AbstractPartRenderer.OWNING_ME) == info.itemElement
							|| cti.getData(AbstractPartRenderer.OWNING_ME) == info.itemElementRef) {
						Rectangle itemRect = cti.getBounds();
						itemRect.width = 3;
						return cti.getDisplay().map(cti.getParent(), null, itemRect);
					}
				}
			}
		} else {
			if (ctf.getItemCount() == 0) {
				Rectangle ctfBounds = ctf.getBounds();
				ctfBounds.height = ctf.getTabHeight();
				ctfBounds.width = 3;
				return ctf.getDisplay().map(ctf, null, ctfBounds);
			}
			CTabItem cti = ctf.getItem(ctf.getItemCount() - 1);
			Rectangle itemRect = cti.getBounds();
			itemRect.x = (itemRect.x + itemRect.width) - 3;
			itemRect.width = 3;
			return cti.getDisplay().map(cti.getParent(), null, itemRect);
		}
		return null;
	}
}