Application Menu broken :(

This *was* working... not sure what version it broke in, but had to be pretty recent. Was also broken in 520. Thats the earliest one I have.

My main window is named "mainWindow":

<ribbon:RibbonWindow ... Name="mainWindow" ... />

Here are two buttons in my Application Menu:

<ribbon:Button Id="Save" Command="ApplicationCommands.Save" KeyTipAccessText="S" IsEnabled="{Binding ElementName=mainWindow, Path=IsTemplateSetLoaded}" />

<ribbon:Button Id="SaveAs" Command="ApplicationCommands.SaveAs" KeyTipAccessText="A" IsEnabled="{Binding ElementName=mainWindow, Path=IsTemplateSetLoaded}" />

Here is my property registration:

private static readonly DependencyPropertyKey IsTemplateSetLoadedProperty = DependencyProperty.RegisterReadOnly("IsTemplateSetLoaded",
typeof(bool), typeof(MainWindow), new PropertyMetadata(false));

I have made sure I'm not setting IsTemplateSetLoadedProperty anywhere. So its value is false.

Neither command is disabled in the Application menu. If I hardcode IsEnabled="False", they are disabled. If I give the buttons names and set IsEnabled=false; via code, that works too. Just not the data binding.

I'm using the classic ribbon, but it doesn't work with the scenic layout either.

P.S. I have a few buttons in the ribbon itself that use the same exact binding, and those work fine. So it is specific to the application menu.


[Modified at 06/04/2010 07:10 PM]