Created attachment 33762 [details]
testcase for the bug
If I create an <option> element with title="option's title text" in a <select>, the tooltip will not be shown.
Created attachment 33763 [details]
Created attachment 33764 [details]
Additionally, the W3C HTML4.01 Specification defines  that <option> can have a title attribute.
Also Mozilla Firefox and Microsoft Internet Explorer 7+ do this well.
This is trivial to fix on Mac, but somewhat more involved on other platforms.
Created attachment 33851 [details]
Patch for the Mac part of this
I'll clone this bug to track fixing this for other platforms after this is landed.
Landed in r46617.
Bug 27864 tracks fixing this for other platforms.