Apply button not appearing after an edit

Ive been editing away happily this morning and now suddenly the apply button is not appearing after and edit. I tried asking it to reapply, but it doesnt make any difference. One thing I notice is that it doesnt show the file name it’s editing like it usually does, just at the top left of where it generates the code.

Does anyone have any ideas on why this is happeneing or how to get it back to normal?