Bug 299438 [CommonNavigator] CNF viewer state non properly reset when NCEs are activated or deactivated
The map of the objects to the NCEs should be reset whenever the NCEs associated with the viewer to change to avoid having stale label information. This has shown up when looking at the CNF tests that change the viewer.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/StructuredViewer.java
/*
	 * (non-Javadoc) Method declared on IPostSelectionProvider.
	 */
	public void addPostSelectionChangedListener(ISelectionChangedListener listener) {
		postSelectionChangedListeners.add(listener);
	}
	/**
	 * Adds support for dragging items out of this viewer via a user
	 * drag-and-drop operation.
	 * 
	 * @param operations
	 *            a bitwise OR of the supported drag and drop operation types (
	 *            <code>DROP_COPY</code>,<code>DROP_LINK</code>, and
	 *            <code>DROP_MOVE</code>)
	 * @param transferTypes
	 *            the transfer types that are supported by the drag operation
	 * @param listener
	 *            the callback that will be invoked to set the drag data and to
	 *            cleanup after the drag and drop operation finishes
	 * @see org.eclipse.swt.dnd.DND
	 */
	public void addDragSupport(int operations, Transfer[] transferTypes, DragSourceListener listener) {
		Control myControl = getControl();
		final DragSource dragSource = new DragSource(myControl, operations);
		dragSource.setTransfer(transferTypes);
		dragSource.addDragListener(listener);
	}
	/**
	 * Adds support for dropping items into this viewer via a user drag-and-drop
	 * operation.