Bug 305703 [Viewers][CommonNavigator] remembered contributions can leak when using filters
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
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));
			}
		} finally {
			setBusy(oldBusy);
		}
	}
	/**
	 * 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