To reproduce the bug:
- On English Wiktionary, as an admin, choose to delete a page.
- Focus the text box labelled "Other/additional reason" (by clicking or tabbing).
- Press Enter.
Expected behaviour: I am in a form's text box, so Enter should submit the form.
Actual behaviour: the "Reason" dropdown list drops down. (Truly bizarre: I have never before seen a UI where you could drop down a list using the keyboard when the list wasn't even focused!)