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

There are more cases described in #8401.

[Jakub Ś]

Reproducible form CKEditor 3.0.

NOTES:
Till CKE 3.1.1 it was impossible to access radio buttons with TAB key. From CKE 3.2 it has been possible to access radio buttons but impossible to leave them.

Sometimes if you press TAB button quickly two times the focus will jump on OK or Cancel button.