I did some regression testing:

OK:
OSX 10.6 / Safari 5.1.7

not OK:
OSX 10.6 / Firefox 13.0.1
OSX 10.6 / Chrome 21.0
OSX 10.6 / Chromium 23.0
OSX 10.6 / Opera 12.02
Debian 6 / Iceweasel (Firefox) 3.5.16
Ubuntu 12.04 / Opera 11.52
iOS 5 (iPad) / Safari
iOS 5 (iPad) / Mercury 6.0.1
iOS 5 (iPad) / Atomic Web 6.0.1
XP / IE8

the test with XP was made with the company laptop via VPN and our company network, all others at home with my ISP through my private LAN