Found on svwp, version: 1.23wmf12 (rMW36f1e5cbb12a)
Steps to reproduce:
- Use firefox 26
- Log in
- Open Special:Block
- The "target" field (mw-bi-target) should be in focus automatically
- Press tab to the "duration" (mw-input-wpExpiry) and select a duration in the dropdown by arrow up/down
- Press tab to move to next in tab-index, the marker should now disapear as the freetext field to enter duration (mw-input-wpExpiry-other) is hidden.
- Press tab again, the expeted behaviour should be that the reason dropdown (mw-input-wpReason) should be selected. What happens is that the search field (searchInput) is selected
mw-bi-target has tabindex 1
mw-input-wpExpiry & mw-input-wpExpiry-other has tabindex 2
After that there are no more form fields that uses tabindex.
Using firebug and modifying the DOM I note that adding tabindex = 3 to mw-input-wpReason let's me tab to that select element after wp-input-wpExpiry-other.