I’m going to pause on this for now, but I’ll see about looking at it next time I go digging. I wouldn’t be upset if @guu ends up fixing it in the mean time though. 
And it makes sense that the various keyboard issues probably have the same root cause.
The ones I know about are:
- exiting the editor with unsaved changes has weird behavior
- input is corrupted when using INPUT in MMBasic
These keyboard related bugs have already been fixed in my repo:
- missing keyboard mappings/behavior for some keys
- mishandled line endings for INPUT/PRINT (which didn’t have a bug, but was a single line change in Editor.c in my repo compared to guu’s repo.