Bug 25827 Disposing of MemberFilterActionGroup
Build 2.0.2 and 2.1 When investigating an editor memory leak PR we found out that this group has a dispose method which is never called. When we then called from the editor it throw an exeption (viewer was disposed). Don't know if the group really needs dispose() if so it should get called.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/typehierarchy/TypeHierarchyViewPart.java
viewer.setSelection(elem != null ? new StructuredSelection(elem) : StructuredSelection.EMPTY, reveal);
		viewer.addSelectionChangedListener(fSelectionChangedListener);
	}
	
	private void internalSelectMember(IMember member) {
		fMethodsViewer.removeSelectionChangedListener(fSelectionChangedListener);
		fMethodsViewer.setSelection(member != null ? new StructuredSelection(member) : StructuredSelection.EMPTY);
		fMethodsViewer.addSelectionChangedListener(fSelectionChangedListener);
	}	
	
	/**
	 * When the input changed or the hierarchy pane becomes visible,
	 * <code>updateHierarchyViewer<code> brings up the correct view and refreshes
	 * the current tree
	 */
	private void updateHierarchyViewer() {
		if (fInputElement == null) {
			fPagebook.showPage(fNoHierarchyShownLabel);
		} else {
			if (getCurrentViewer().containsElements() != null) {
				Runnable runnable= new Runnable() {
					public void run() {
						getCurrentViewer().updateContent(); 
					}
				};
				BusyIndicator.showWhile(getDisplay(), runnable);
				if (!isChildVisible(fViewerbook, getCurrentViewer().getControl())) {
					setViewerVisibility(true);
				}	
			} else {