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
* @param event
	 *            the SWT selection event
	 */
	protected void handleOpen(SelectionEvent event) {
		Control control = getControl();
		if (control != null && !control.isDisposed()) {
			ISelection selection = getSelection();
			fireOpen(new OpenEvent(this, selection));
		}
	}
	/**
	 * Handles an invalid selection.
	 * <p>
	 * This framework method is called if a model change picked up by a viewer
	 * results in an invalid selection. For instance if an element contained in
	 * the selection has been removed from the viewer, the viewer is free to
	 * either remove the element from the selection or to pick another element
	 * as its new selection. The default implementation of this method calls
	 * <code>updateSelection</code>. Subclasses may override it to implement
	 * a different strategy for picking a new selection when the old selection
	 * becomes invalid.
	 * </p>
	 * 
	 * @param invalidSelection
	 *            the selection before the viewer was updated
	 * @param newSelection
	 *            the selection after the update, or <code>null</code> if none
	 */
	protected void handleInvalidSelection(ISelection invalidSelection, ISelection newSelection) {
		updateSelection(newSelection);