Add inline editability to tables

It will be a good improvement to add in-line add/edit functionality for RadioGroup file types. Right now when you want to add new item to the table you should click New Instance button:


And after that you doesn't see already existing values. When you save changes, to edit any item you should click on Edit button:

And again you doesn't see other values.

Expected behaviour will be ability to edit Value/Text in-line without switching to another editor for items creation/edition.

Delete button also can be narrow and provide more space for Value/Text fields.