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
preservingSelection(new Runnable() {
			public void run() {
				Control tree = getControl();
				boolean useRedraw = true;
				
				
				if (useRedraw) {
					tree.setRedraw(false);
				}
				removeAll(tree);
				tree.setData(getRoot());
				internalInitializeTree(tree);
				if (useRedraw) {
					tree.setRedraw(true);
				}
			}
		});
	}
	/**
	 * @param tree
	 */
	protected void internalInitializeTree(Control tree) {
		createChildren(tree);
		internalExpandToLevel(tree, expandToLevel);
	}
	/**
	 * Recursively collapses the subtree rooted at the given widget to the given
	 * level.
	 * <p>
	 * </p>