Bug 125011 [Contributions] ActionContributionItem should use text for tooltip in toolitems
If an action is added to a toolbar, and it has a name, but no tooltip set, the name should be used as the tooltip (except when the text is actually displayed on the toolitem using setText()) Clients sometimes forget to set the tooltip text when no specific tooltip message exists.
bundles/org.eclipse.jface/src/org/eclipse/jface/action/ActionContributionItem.java
* Creates a new contribution item from the given action. The id of the
     * action is used as the id of the item.
     * 
     * @param action
     *            the action
     */
    public ActionContributionItem(IAction action) {
        super(action.getId());
        this.action = action;
    }
    /**
     * Handles a property change event on the action (forwarded by nested listener).
     */
    private void actionPropertyChange(final PropertyChangeEvent e) {
        
        if (isVisible() && widget != null) {
            Display display = widget.getDisplay();
            if (display.getThread() == Thread.currentThread()) {
                update(e.getProperty());
            } else {
                display.asyncExec(new Runnable() {
                    public void run() {
                        update(e.getProperty());
                    }
                });
            }
        }
    }
    /**
     * Compares this action contribution item with another object.