Bug 28575 Hierarchy view updates items twice [type hierarchy]
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/typehierarchy/TypeHierarchyViewPart.java
new NewWizardsActionGroup(this.getSite()),
				new OpenEditorActionGroup(this), 
				new OpenViewActionGroup(this), 
				new ShowActionGroup(this), 
				fCCPActionGroup= new CCPActionGroup(this), 
				new RefactorActionGroup(this),
				new GenerateActionGroup(this),
				new JavaSearchActionGroup(this)});
		
		fActionGroups.fillActionBars(actionBars);
		fSelectAllAction= new SelectAllAction(fMethodsViewer);
		
		actionBars.setGlobalActionHandler(IWorkbenchActionConstants.SELECT_ALL, fSelectAllAction);
		
		initDragAndDrop();		
	}
	/**
	 * called from ToggleOrientationAction.
	 * @param orientation VIEW_ORIENTATION_SINGLE, VIEW_ORIENTATION_HORIZONTAL or VIEW_ORIENTATION_VERTICAL
	 */	
	public void setOrientation(int orientation) {
		if (fCurrentOrientation != orientation) {
			boolean methodViewerNeedsUpdate= false;
			
			if (fMethodViewerViewForm != null && !fMethodViewerViewForm.isDisposed()
					&& fTypeMethodsSplitter != null && !fTypeMethodsSplitter.isDisposed()) {
				if (orientation == VIEW_ORIENTATION_SINGLE) {
					fMethodViewerViewForm.setVisible(false);
					enableMemberFilter(false);
					updateMethodViewer(null);