Bug 55604 [implementation] JavaOutlinePage should dispose CustomFiltersActionGroup
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaOutlinePage.java
/*
	 * @see ISelectionProvider#getSelection()
	 */
	public ISelection getSelection() {
		if (fOutlineViewer == null)
			return StructuredSelection.EMPTY;
		return fOutlineViewer.getSelection();
	}
	
	/*
	 * @see org.eclipse.jface.text.IPostSelectionProvider#addPostSelectionChangedListener(org.eclipse.jface.viewers.ISelectionChangedListener)
	 */
	public void addPostSelectionChangedListener(ISelectionChangedListener listener) {
		if (fOutlineViewer != null)
			fOutlineViewer.addPostSelectionChangedListener(listener);
		else
			fPostSelectionChangedListeners.add(listener);
	}
	
	/*
	 * @see org.eclipse.jface.text.IPostSelectionProvider#removePostSelectionChangedListener(org.eclipse.jface.viewers.ISelectionChangedListener)
	 */
	public void removePostSelectionChangedListener(ISelectionChangedListener listener) {
		if (fOutlineViewer != null)
			fOutlineViewer.removePostSelectionChangedListener(listener);
		else
			fPostSelectionChangedListeners.remove(listener);	
	}
	
	private void registerToolbarActions(IActionBars actionBars) {