Bug 6970 Hierarchy tick marks out of sync
Build 20011211 - open org.eclipse.jface.actions.IAction - add method: public void setMenuCreator(IMenuCreator creator) { } - build - error mark shows up in task list and editor tab (method shouldn't have body), but not in hierarchy - make mod and save - hierarchy now shows tick - fix the problem and build - hierarchy still shows tick - make mod and save - hierarchy is now consistent
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/typehierarchy/TypeHierarchyViewer.java
* Returns true if the hierarchy contains elements. Returns one of them
	 * With member filtering it is possible that no elements are visible
	 */ 
	public Object containsElements() {
		TypeHierarchyContentProvider contentProvider= getHierarchyContentProvider();
		if (contentProvider != null) {
			Object[] elements= contentProvider.getElements(null);
			if (elements.length > 0) {
				return elements[0];
			}
		}
		return null;
	}	
	
	/**
	 * Returns true if the hierarchy contains elements. Returns one of them
	 * With member filtering it is possible that no elements are visible
	 */ 
	public IType getTreeRootType() {
		TypeHierarchyContentProvider contentProvider= getHierarchyContentProvider();
		if (contentProvider != null) {		
			Object[] elements=  contentProvider.getElements(null);
			if (elements.length > 0 && elements[0] instanceof IType) {
				return (IType) elements[0];
			}
		}
		return null;
	}