Required validation of TextField args is working
The validator was being incorrectly removed. Added some short-circuit logic to prevent it.
The issue where validation would work during app creation (directly after adding the argument) was due to the argument's validator list being null when it is first created. Once the app is saved and re-opened, this collection is just an empty list. Since the list was empty, it still allowed the edit/refresh logic to hit the code block which removed the EmptyValidator.
CORE-5465
Applied argument select css to the subeditor
There was a mismatch in where the argument select css class was being placed. The WYSIWYG delete handler was applying it to the argument editor factory's subEditor, which seems to be the appropriate choice here, so the ArgGrpEditor was updated to match.
CORE-5526
Corrected which argument is selected after arg del
CORE-5527