Bug 156537 [Viewers] Virtual tree viewer does not populate with initial children
I20060830-1650 When a tree viewer is created with the SWT.Vitrual flag and uses an ILazyTreeContentProvider, the viewew does not populate with the initial children in the model. The method TreeViewer.createChildren(Widget) only updates existing items if the parent (root)element has been mapped to data, and does not query the content provider for the number of children it has. Attached is a sample plug-in showing the problem. The tree "model" looks like this: root one two three When the input is set to the viewer ("root") a call is made to "createChildren", but the content provider is never used.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
Item item = (Item) widget;
			
			if (fullMap) {
				associate(element, item);
			} else {
				Object data = item.getData();
				if (data != null) {
					unmapElement(data, item);
				}
				item.setData(element);
				mapElement(element, item);
			}
			
			SafeRunnable.run(new UpdateItemSafeRunnable(item, element));
		}
	}
	/**
	 * Expands all nodes of the viewer's tree, starting with the root. This
	 * method is equivalent to <code>expandToLevel(ALL_LEVELS)</code>.
	 */
	public void expandAll() {
		expandToLevel(ALL_LEVELS);
	}
	/**
	 * Expands the root of the viewer's tree to the given level.
	 * 
	 * @param level
	 *            non-negative level, or <code>ALL_LEVELS</code> to expand all
	 *            levels of the tree
	 */