Bug 323832 [UI] SashContainers are not being removed when unneeded
Start with a fresh workspace Drag the Problems view to the right of its current stack Drag it back... The problem is that the original drag created an MPartSashContainer to host the new stack but the drag back doesn't remove it (i.e. after dragging the Problems view back to its original stack there's now an MPSC with *only* the one stack in it).
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/ModelServiceImpl.java
}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.workbench.modeling.EModelService#detach(org.eclipse.e4.ui.model.application
	 * .MPartSashContainerElement)
	 */
	public void detach(MPartSashContainerElement element, int x, int y, int width, int height) {
		
		MUIElement curParent = element.getParent();
		while (curParent != null && !(curParent instanceof MPerspective)
				&& !(curParent instanceof MWindow))
			curParent = curParent.getParent();
		if (curParent == null)
			return; 
		MTrimmedWindow newWindow = BasicFactoryImpl.INSTANCE.createTrimmedWindow();
		
		newWindow.setX(x);
		newWindow.setY(y);
		newWindow.setWidth(width);
		newWindow.setHeight(height);
		element.getParent().getChildren().remove(element);
		MWindowElement uiRoot = wrapElementForWindow(element);
		newWindow.getChildren().add(uiRoot);
		if (curParent instanceof MPerspective) {
			MPerspective persp = (MPerspective) curParent;
			persp.getWindows().add(newWindow);
			MWindow window = getTopLevelWindowFor(persp);
			IPresentationEngine renderingEngine = persp.getContext().get(IPresentationEngine.class);