Bug 305739 [viewers] #expandToLevel(Object, level) retrieves all children when virtual
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
try {
			for (int i = 0; i < listeners.length; ++i) {
				final ITreeViewerListener l = (ITreeViewerListener) listeners[i];
				SafeRunnable.run(new SafeRunnable() {
					public void run() {
						l.treeExpanded(event);
					}
				});
			}
		} finally {
			setBusy(oldBusy);
		}
	}
	/**
	 * Returns the auto-expand level.
	 *
	 * @return non-negative level, or <code>ALL_LEVELS</code> if all levels of
	 *         the tree are expanded automatically
	 * @see #setAutoExpandLevel
	 */
	public int getAutoExpandLevel() {
		return expandToLevel;
	}
	/**
	 * Returns the SWT child items for the given SWT widget.
	 *
	 * @param widget
	 *            the widget
	 * @return the child items
	 */