Bug 167323 [Viewers]Open AbstractTreeViewer for external widget implementors
As reported by Ross Camara AbstractTreeViewer would work for nebula if we would open the API a bit. Boris and I decided that we will do this in 2 steps: 1. open the API 2. moving the Virtual-Support bits from TreeViewer to AbstractTreeViewer when the nebula grid provides virtual support.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
}
		internalReconcileParentItems(parentItems);
	}
	/**
	 * @param parentItems
	 */
	private void internalReconcileParentItems(CustomHashtable parentItems) {
		Control tree = getControl();
		for (Enumeration e = parentItems.keys(); e.hasMoreElements();) {
			Item parentItem = (Item) e.nextElement();
			if (parentItem.isDisposed()) {
				continue;
			}
			if (!getExpanded(parentItem) && getItemCount(parentItem) == 0) {
				
				if (isExpandable(parentItem, null, parentItem.getData())) {
					newItem(parentItem, SWT.NULL, -1);
				} else {
					
					tree.redraw();
				}
			}
		}
	}
	/**
	 * Removes the given elements from this viewer, whenever those elements
	 * appear as children of the given parent.
	 * 
	 * @param parent the parent element
	 * @param elements