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
action.setChecked(fCurrentViewerIndex == action.getViewerIndex());
		}
	}
	/**
	 * Gets the curret active view index.
	 */		
	public int getViewIndex() {
		return fCurrentViewerIndex;
	}
	
	private TypeHierarchyViewer getCurrentViewer() {
		return fAllViewers[fCurrentViewerIndex];
	}
	/**
	 * called from EnableMemberFilterAction.
	 * Must be called after creation of the viewpart.
	 */	
	public void enableMemberFilter(boolean on) {
		if (on != fIsEnableMemberFilter) {
			fIsEnableMemberFilter= on;
			if (!on) {
				IType methodViewerInput= (IType) fMethodsViewer.getInput();
				setMemberFilter(null);
				updateHierarchyViewer();
				updateTitle();
			
				if (methodViewerInput != null && getCurrentViewer().isElementShown(methodViewerInput)) {
					
					internalSelectType(methodViewerInput, true);
				} else if (fSelectedType != null) {