Bug 84314 [Viewers] Need to allow mapping elements to multiple widgets/items
One of the projects I am working on is using an essentially graph structured dependancy model and we use TableTreeViewer for browsing (drilling down) through this graph. The nature of the model is such that the same model element can occur in multiple positions (paths) of the three. Current implementation of the TreeViewer and TableTreeViewer do not support such one-to-many mapping of model elements to widgets, leading to loads of unnecessary overhead to enshure that correct items will get updated. Suggestion: Element -> Item mapper should allow returning of more than one item per model element that is associated with this element.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/StructuredViewer.java
*         <code>false</code> if disabled
	 */
	protected boolean usingElementMap() {
		return elementMap != null;
	}
	/* (non-Javadoc)
	 * @see org.eclipse.jface.viewers.ContentViewer#setLabelProvider(org.eclipse.jface.viewers.IBaseLabelProvider)
	 */
	public void setLabelProvider(IBaseLabelProvider labelProvider) {
		if (labelProvider instanceof IColorProvider || labelProvider instanceof IFontProvider)
			colorAndFontCollector = new ColorAndFontCollectorWithProviders(labelProvider);
		else
			colorAndFontCollector = new ColorAndFontCollector();
		super.setLabelProvider(labelProvider);
		
	}
	
	/**
	 * Build a label up for the element using the supplied label provider.
	 * @param updateLabel The ViewerLabel to collect the result in
	 * @param element The element being decorated.
	 */
	protected void buildLabel(ViewerLabel updateLabel, Object element){
		if (getLabelProvider() instanceof IViewerLabelProvider) {
			IViewerLabelProvider itemProvider = (IViewerLabelProvider) getLabelProvider();
			itemProvider.updateLabel(updateLabel, element);
            		
			colorAndFontCollector.setUsedDecorators();
			
			if(updateLabel.hasNewBackground())