Bug 5492 Open in Hierarchy method list is enabled even when nothing is selected
206 1) Ensure no item is selected in the hierachy view's member list 2) Right click - not on an item 3) Open is present and enabled 4) Select Open, nothing happens
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/typehierarchy/TypeHierarchyViewer.java
menu.appendToGroup(IContextMenuConstants.GROUP_SHOW, fShowInPackageViewAction);
		ContextMenuGroup.add(menu, fStandardGroups, this);
	}
	/**
	 * Set the member filter
	 */
	public void setMemberFilter(IMember[] memberFilter) {
		getHierarchyContentProvider().setMemberFilter(memberFilter);
	}
	/**
	 * Returns if method filtering is enabled.
	 */	
	public boolean isMethodFiltering() {
		return getHierarchyContentProvider().getMemberFilter() != null;
	}
		
	/**
	 * 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() {
		Object[] elements=  ((IStructuredContentProvider)getContentProvider()).getElements(null);
		if (elements.length > 0) {
			return elements[0];
		}
		return null;
	}