widget crashes when using Menu2InputDelegate

sdk 4.1.7, win10, eclipse

f6p 24.10

after this code

pushView(new SamplesMenu(), new WatchUi.Menu2InputDelegate() , WatchUi.SLIDE_IMMEDIATE);

menu is shown but after pressing BACK app crashes on device (ERA shows error but no backtrace), on sim is ok

workaround is

class SamplesMenuInputDelegate extends WatchUi.Menu2InputDelegate
{
    function initialize()
    {
        Menu2InputDelegate.initialize();
    }
}

pushView(new SamplesMenu(), new SamplesMenuInputDelegate() , WatchUi.SLIDE_IMMEDIATE);