Bug 74163 [IDE] Tips and Tricks dialog; disable OK if no selection
OK should be disabled if one has not selected one entry in the list box above.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/TipsAndTricksAction.java
ActionFactory.IWorkbenchAction {
    /**
     * The workbench window this action is registered with.
     */
    private IWorkbenchWindow workbenchWindow;
    /**
     * Create an instance of this class.
     * 
     * @param window the window