I believe that when you save, the application  "compiles".... Not really but
that's another story... the code to P-Code.

On the Debug menu in the IDE there is an option  to Compile. Try doing that
and see what happens.

Are you using Option Explicit at the top of the module?

Try looking at the vlue of the text *and the variable type* in the watch
window.
You could also check what the active workbook/worksheet is at the same time.

Callbacks can be a bit complex sometimes.