Got it! It was a bug in v2.0-dev firmware. The LedDisplayTextField widget was trying to reference the last selected widget (APP->event->selectedWidget) which is not defined in firmware (APP->event was a nullptr). I removed that call and also made it so the rest of the APP context objects are defined now.
@tony10000 's example patch plays now.
Sorry for any headache you had trying to find that one…
I’ll push this release now (it’ll be dev-12.13)