help with compatibility

I have two extensions which both modify the "charsheet_main" windowclass of 3.5E via merge="join"
record_char_main.xml
and
record_char_main.xml

Which don't re-use any names or use any of the same templates.
When I comment out <sheetdata> to </sheetdata> in the second file, the incompatibility is still there. when I take it up one level to also comment out the (now empty) windowclass, it suddenly is compatible.
It works fine in Unity but is showing this behavior in Classic and I don't get it because overlaying an empty windowclass shouldn't cause incompatibilities as far as I can tell...

There's an issue in FGC where multiple window class merges don't load scripts correctly; that is fixed in FGU. I'm assuming that is the issue that you are seeing.

Right now, we don't have any plans to spend development cycles on FGC to fix this; since we're barreling towards FGU full release.

Regards,
JPG