I think a panel extends viewgroup so it should.
Though the only experience i had was to inflate a layout for remoteviews, i never saw any restrictions on it.
Just to bring this back to life with another cry for help. Yes still trying.....
The Android Notification objects' method to set a custom view requires that a RemoteViews object is passed. Is there ANY way to get a Designer layout cast to a RemoteViews. This would allow custom notification layouts to be built in the designer.....
A designer layout is converted to RemoveViews when you create a widget. It will not be easy to use this mechanism as it is built specifically for widgets support.
Check anywheresoftware.b4a.objects.RemoteViews.createRemoveViews.