Multiple Choice Ques: Tab key unselects Correct Answer radio button in Firefox

Using the Tab key on keyboard normally moves from text box to text box, but in Firefox it moves from text box to radio button to text box. If a Correct Answer is selected, using Tab to fill in other answer options removes the Correct Answer selection. The question can be saved (even with no Correct Answer selected) and will be added to the test. In the Questions: Test Title page, the question is shown with D marked as correct.

To Reproduce:

1. Create an assessment
2. Insert a Multiple Choice question
3. Enter question text
4. Select radio button next to A for Correct Answer
5. Type in the A text box
6. Use Tab key twice to type in B text box - note A is no longer selected
7. Continue using Tab to type in C and D text boxes
8. Click Save
9. Note question is listed with D as Correct Answer