Bug 326087 StackRenderer arbitrarily changes selected element when MPartStack is being unrendered
1. Open two files. 2. Activate the editor in the back. 3. Restart 4. The file in the wrong is active now. :O
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/StackRenderer.java
return null;
	}
	@Override
	public void hideChild(MElementContainer<MUIElement> parentElement,
			MUIElement child) {
		super.hideChild(parentElement, child);
		CTabFolder ctf = (CTabFolder) parentElement.getWidget();
		if (ctf == null)
			return;
		
		CTabItem cti = findItemForPart(child, parentElement);
		if (cti != null) {
			cti.setControl(null);
			cti.dispose();
		}
		
		if (parentElement.getSelectedElement() == child) {
			if (ctf.getTopRight() != null) {
				Control curTB = ctf.getTopRight();
				ctf.setTopRight(null);
				if (!curTB.isDisposed()) {
					MUIElement tbME = (MUIElement) curTB
							.getData(AbstractPartRenderer.OWNING_ME);
					if (tbME instanceof MRenderedToolBar)
						renderer.removeGui(tbME);
					else
						curTB.dispose();
				}
			}