Blizzard has announced that they are aware of an issue regarding the UI windows for socketing and enchanting on Cataclysm Classic PTR and are working on a fix, noting that it will require a PTR update.
We are aware of and working to fix an issue with pop-up windows impacting socketing and enchanting.
The fix will likely require us the update the PTR.
We’ll let you know when we deploy the fix.