Tab Order broken when we have radio buttons inside the dialog

[Satya Minnekanti]

To reproduce the defect:

Use CKEditor Dialog API Sample and change the dialog Definition to add Radio buttons to the dialog. (I have attached the dialog definition that i used)

Press Tab after you reached the Radio buttons.

Expected Result: Focus goes to OK button.

Actual Result: Focus stays on the radio button itself, even we press Tab any number of times focus stays on the radio button.

This will cause an Accessibility Failure