getting the highlighting filetype right (ObjC/ObjC++)

Hi,

I cannot seem to convince KDevelop (5.3 branch) to respect the fact that any .m (.mm) files I might open are ObjC (ObjC++). Support for this language is flaky enough as it is, so not getting the highlighting right is rather frustrating. I did manage to avoid misinterpretation as Mathematica or Matlab files, but not as Magma.

I'd delete the entire Magma option if I could but can't. Removing the .m extension from the Magma type def (in Settings/Open,Save/Modes&FileTypes) and setting the ObjC def priority to a non-zero number don't help. That priority field lacks a tooltip so one cannot know (easily) if 0 is the lowest or the highest priority...

So, how can I get this right without hardcoding the extension/type association somewhere in KDevelop?

Thanks,
René