Bug 65762 [Viewers] Need to back out of change to AbstractTreeViewer.isExpandable
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
/**
	 * 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
	 */
	public void expandToLevel(int level) {
		expandToLevel(getRoot(), level);
	}
	/**
	 * Expands all ancestors of the given element so that the given element
	 * becomes visible in this viewer's tree control, and then expands the
	 * subtree rooted at the given element to the given level.
	 * 
	 * @param element
	 *           the element
	 * @param level
	 *           non-negative level, or <code>ALL_LEVELS</code> to expand all
	 *           levels of the tree
	 */
	public void expandToLevel(Object element, int level) {
		Widget w = internalExpand(element, true);