deleting reference the dialog box goes grey

This started yesterday. Normally when I highlight a reference in the reference dialog box and delete is an Alert box pops up asking if I want to detach it AT THIS POINT I usually hit Enter and the ref is detached.

Now the Alert box is grey meaning hitting the Enter button doesn't do anything UNTIL I click on the box making it "blue" like normal. This might seem small but it really is annoying having to put my mouse that Alert box every time I need to delete a reference file, which is a task I have been assigned to on over 100 files. Unfortunately, the references are not consistent so I must go into each file.

Does anyone have an idea of why this has started to happen?

Thank you