Bug 63420 [R21PRES] Flash on tab switch
bundles/org.eclipse.ui.presentations.r21/src/org/eclipse/ui/internal/presentations/R21EditorStackPresentation.java
updateGradient();
	}
	
    /**
     * Restores a presentation from a previously stored state
     * 
     * @param serializer (not null)
     * @param savedState (not null)
     */
    public void restoreState(IPresentationSerializer serializer, IMemento savedState) {
        IMemento[] parts = savedState.getChildren(IWorkbenchConstants.TAG_PART);
        
        for (int idx = 0; idx < parts.length; idx++) {
            String id = parts[idx].getString(IWorkbenchConstants.TAG_ID);
            
            if (id != null) {
                IPresentablePart part = serializer.getPart(id);
                
                if (part != null) {
                    addPart(part, tabFolder.getItemCount());
                }
            } 
        }
    }
    
    
    /* (non-Javadoc)
     * @see org.eclipse.ui.presentations.StackPresentation#saveState(org.eclipse.ui.presentations.IPresentationSerializer, org.eclipse.ui.IMemento)
     */
    public void saveState(IPresentationSerializer context, IMemento memento) {