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/workbench/modeling/EModelService.java
*/
	public MUIElement find(String id, MUIElement searchRoot);
	/**
	 * Locate the context that is closest to the given element in the parent hierarchy. It does not
	 * include the context of the supplied element (should it have one).
	 * 
	 * @param element
	 *            the element to locate parent context for
	 * @return the containing context for this element
	 */
	public IEclipseContext getContainingContext(MUIElement element);
	/**
	 * Ensures that the given element is visible in the UI
	 * 
	 * @param window
	 *            The containing MWindow
	 * @param element
	 *            The element to bring to the top
	 */
	public void bringToTop(MWindow window, MUIElement element);
	/**
	 * Given a containing MWindow find the MPlaceholder that is currently being used to host the
	 * given element (if any)
	 * 
	 * @param window
	 *            The containing window
	 * @param element
	 *            The element to find the MPlaceholder for
	 * @return the MPlaceholder or null if none is found
	 */