This is bug 759993 but for mac only.

The problem is that nsChildView always seems to return 0,0 for the position from GetScreenBounds and GetClientBounds.

Comment on attachment 702442 [details] [diff] [review] patch Looks fine to me.

Comment on attachment 702442 [details] [diff] [review] patch This turns out to fix the regression bug 843675, so because of that I think we should consider this for uplift to beta (it is on aurora already since it landed before the migration). [Approval Request Comment] Bug caused by (feature/regressing bug #): bug 843675 (the bug we aim to fix) was caused by bug 759993 User impact if declined: select drop downs that have CSS transform scale(1) won't work on Mac, which seems minor but the issue was reported a few days after it appeared on the release channel, so it appears this is an issue for some people. Testing completed (on m-c, etc.): we've had this on central for over a month now and no problems reported Risk to taking this patch (and alternatives if risky): should be safe, only risk is if we had code depending on the old broken behaviour. we haven't found any in a month, so probably not. String or UUID changes made by this patch: none

Comment on attachment 702442 [details] [diff] [review] patch Yes, let's get this 19 regression fix into FF20.

Verified fixed FF 20b2, 21.0a2 (2013-02-27) Mac OS X 10.8.2