Picklist disabled, but not really...

I have a picklist that has Enable conditions that should disable it when another field is set to a certain value. It appears to work. The field is gray, and the message shows up, but I am allowed to change the value and clicking save commits the change.

The same enable conditions work perfectly on a text field. Any thoughts on why this is?

Hey Andrew, i tried to look at it, but when reproducing the Error, everything seems to work, do you mind sharing the XML so i can have a look at you problem in detail?