Cannot read properties of undefined using a getter accessing outer scope variable

[emavitta]

As specified in this discussion, when i try to access some properties of a parent in a child getter, i get an error and the devtools stop working. The code however still works.
I made an example that works perfectly in the online editor, but once downloaded and tested it with devtools enabled, it stops working.

[emavitta]

If i comment out the if statment at line 390 in backend.js it work as intendend. Still just a quick fix to make it work while developing...