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/javaeditor/JavaOutlinePage.java
/* (non-Javadoc)
	 * Method declared on Page
	 */
	public void init(IPageSite pageSite) {
		super.init(pageSite);
	}
	
	private void doPropertyChange(PropertyChangeEvent event) {
		if (fOutlineViewer != null) {
			if (MembersOrderPreferencePage.PREF_OUTLINE_SORT_OPTION.equals(event.getProperty())) {
				fOutlineViewer.refresh();
			}
		}
	}	
	
	/*
	 * @see ISelectionProvider#addSelectionChangedListener(ISelectionChangedListener)
	 */
	public void addSelectionChangedListener(ISelectionChangedListener listener) {
		if (fOutlineViewer != null)
			fOutlineViewer.addSelectionChangedListener(listener);
		else
			fSelectionChangedListeners.add(listener);
	}
	
	/*
	 * @see ISelectionProvider#removeSelectionChangedListener(ISelectionChangedListener)
	 */
	public void removeSelectionChangedListener(ISelectionChangedListener listener) {