Hi nemuneko, thanks for reporting this problem with Japanese keyboard shortcut keys.

It may be related to this Qt bug mentioned here:
https://codereview.qt-project.org/c/qt/qtbase/+/95050

There seem to be some fixes in the Qt Mac keymapper since the version that MoI currently uses. Probably the first thing to try is for me to update that and see if that helps.

Can you please try using the attached updated version? To apply it, right click on MoI v4 beta Jan-22-2020.app and choose "Show package contents". Then inside there go to Contents > Frameworks > qt > platforms. Rename the existing libqcocoa.dylib something like libqcocoa.dylib.bak and then put the attached one in place there.

Is there any change in behavior with that in place?

If not it may be difficult for me to fix this since I don't have a Japanese keyboard over here. Maybe I can make a couple of test builds to send to you that could gather more information about how those keys are being processed. I will be away on vacation for this next week so we could try that after I return.

I can reproduce the CapsLock making an "A" (on every 2nd keystroke it appears) so that's one I can dig into more easily. But I think the fix will be to just do nothing, CapsLock isn't meant to be used as a shortcut key.

Thanks,
- Michael