This fails:appBarUtils:AppBarButton IconUri="/Assets/appbar.settings.png" Text="{Binding Loc.AppBarSettings}" Command="{Binding ShowSettings}"but when changed the line to this, it works:appBarUtils:AppBarButton IconUri="/Assets/appbar.settings.png" Text="abcd" Command="{Binding ShowSettings}"fixed it myself by setting dummy text here: public static readonly DependencyProperty TextProperty = DependencyProperty.Register("Text", typeof(string), typeof(AppBarItemBase), new PropertyMetadata("empty", TextPropertyChanged));and changing the constructor like this: public AppBarButton() { _applicationBarItem = new ApplicationBarIconButton(); ChangeText(); // also made it protected SubscribeClickEvent(); }