Is this also the cause for having double dropdowns in Chrome?

Datalists seem to have problems in all browsers:

• Opera already is blacklisted
• Firefox doesn't increase the width, search doesn't start after user selects a suggestion (bug 31654)
• Safari 5 doesn't show the suggestions at all (bug 31768)

Having two different implementations (native datalists vs. self-made list) is confusing when you try to help others figuring out where the problem is, and after the above list of browser bugs I can't believe that any other browser has an implementation that is usable in every situation so I suggest to set
window.os_use_datalist = false
again, i. e. revert revision 79363.

Created attachment 9261
Proposed patch

While I tested the patch I found another problem with HTML5 datalists (tested in Firefox 4, but probably a problem in every implementation):
My testwiki uses German localization, so user pages begin with "Benutzer:" or "Benutzerin:" for females. When datalists are used only those pages were shown, which start with the exact namespace, i. e., typing "User:" didn't show any page, "Benutzer:" showed only pages of male or neutral users, "Benutzerin:" only pages of females. After I disabled datalists all three could be used to show any userpage as it should be.

Attached:

Oh really? We have specific bug about that: bug 31697.

see r100348 for possible fix.