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
* untyped but may safely be assigned to List&lt;MUIElement&gt;.
	 * </p>
	 * 
	 * @param <T>
	 *            The generic type of the returned list
	 * @param searchRoot
	 *            The element at which to start the search. This element must be non-null and is
	 *            included in the search.
	 * @param id
	 *            The ID of the element. May be null to omit the test for this field.
	 * @param clazz
	 *            The class specifier determining the 'instanceof' type of the elements to be found.
	 *            If specified then the returned List will be generically specified as being of this
	 *            type.
	 * @param tagsToMatch
	 *            The list of tags to match. All the tags specified in this list must be defined in
	 *            the search element's tags in order to be a match.
	 * 
	 * @return The generically typed list of matching elements.
	 */
	public <T> List<T> findElements(MUIElement searchRoot, String id, Class<T> clazz,
			List<String> tagsToMatch);
	/**
	 * Returns the first element, recursively searching under the specified search root (inclusive)
	 * 
	 * @param id
	 *            The id to search for, must not be null
	 * @param searchRoot
	 *            The element at which to start the search
	 * @return The first element with a matching id or <code>null</code> if one is not found