WPF menuitem shortcut. Strange behaviour
<p>I create a menu item (context menu if that is of any help) using:</p>

<pre><code>MenuItem menExit = new MenuItem();
menExit.Header = "Exit"; // will be changed later
menExit.Command = UICommands.CmdExit;
menExit.CommandBindings.Add(new CommandBinding(UICommands.CmdExit,     CmdExitExecute, CmdExitCanExecute));
menu.Items.Add(menExit);
</code></pre>

<p>It works very well with one exception. No matter what CmdExitCanExecute returns, the menu item shortcut is ALWAYS grayed out. Note that the text ("Exit") works as intended (grayed out when CmdExitCanExecute returns false and black when true) but not so the shortcut. To make matters more complicated: the shortcut works when I press the key combination. What do I need to do to make the shortcut show the right color? The menu is shown by right clicking a tray icon, but that shouldn't matter, should it?</p>