Bug Report

• Package version(s): 2.23.0

Priorities and help requested (not applicable if asking question):

Are you willing to submit a PR to fix? Yes

Requested priority: Normal

Products/sites affected: VSTS

Describe the issue:

If an or in a DetailsList has been focused using the keyboard, when a user tries to up or down arrow to select and focus a new row, the .is-selected class is not applied to the row. If the row itself has the focus, up/down arrow works.

I believe this was introduced by this PR:

#1530

http://codepen.io/dzearing/pen/EgqMZq

1. Tab to first row using keyboard.
2. Right arrow until focus is on link in 3rd column.
3. Down arrow to move focus to next row.

Expected Results:
.is-selected class is on the 2nd row.

Actual Results:
.is-selected class is not on the 2nd row.
If the user hits down arrow again to move focus to 3rd row, the .is-selected class is added.