Empty field type drop-down list in "Add new field"

[tma-1]

Hello all,

First time poster here. I've been playing around with ProcessWire for some time and am currently in the middle of my first project based entirely on PW.

I have a problem with the field type drop-down list in the "Add new field" tab. All of the sudden it's blank. Am I missing something, or is this an error?

It looks like this, no field types, nothing. I didn't even modify any particular settings in the meantime. Half an hour ago it was working just fine.

Thanks in advance for any help.