"Back 10 sec." button closes and breaks editor windows in tutorial

[Wallby]

Actual Behaviour

Pressing the "Back 10 sec." button will remove any open editor windows.

Expected Behaviour

Pressing the "Back 10 sec." button should act exactly as if pressing a time 10 sec earlier on the timeline, which updates editor windows.

Steps to reproduce it

go to https://hello.processing.org/editor/
skip to a part with an editor window, like (approx) 4:20 on the 2. Shapes tutorial page
now wait at least 10 seconds and then rewind using the "Back 10 sec." button
notice the windows are gone and can only be reopened by going to the first "show" event (so at +- 4:20)

Screenshots of the issue

[shiffman]

Thanks for reporting @Wallby! What browser / browser version / OS? I'll take a look!

[Wallby]

@shiffman Hello, seems like I didn't reply yet. I am not sure now which OS or browser this was.