If someone is interested, there is a patch from Mozilla: https://bugzilla.mozilla.org/show_bug.cgi?id=517422#c11
It must be adapted to Icecat. -- Antonio Trande mailto: sagitterATfedoraproject.org http://www.fedoraos.worpress.com https://fedoraproject.org/wiki/User:Sagitter GPG Key: D400D6C4 -- http://gnuzilla.gnu.org
