WPopupMenu in WidgetSet application gives Wt internal error; code: undefined, description: Cannot read property 'display' of undefined
I'm turning our Application into a WidgetSet in order to avoid the X-Frame-Options but now I run into a problem. Our submenu is not working in the WidgetSet.
We use wt3.7.0
I can reproduce it by adding a menu in the hello example (see attached file)