The Cmd + "+" KeyCharacterCombination does not work reliably on the US English layout. It has reverted to old behavior, namely that you have to first press the + key without Cmd before the system recognizes Cmd + "+".

To reproduce:
Use a US English keyboard or any keyboard where + on the main keyboard requires the shift key.
Run the attached program.
Type Cmd + "+"
Type Cmd + "<"

Results:
Cmd + "+" yields no output but Cmd + "<" does
Cmd + "+" starts working again if you press "+" without Cmd.

Expected results:
Both shortcuts should add some text to the text area.