There is a request pending for this in the bug tracking system with a low-ish priority (P5). I would not depend on this coming to Firefox any time soon. However, if you want to help code it, volunteer assistance is always welcome. Note: It's generally not helpful to add comments to bugs (unless there is a call for test cases), but you can register on the Bugzilla site and "vote" for them to be fixed. See: * [https://bugzilla.mozilla.org/page.cgi?id=etiquette.html Bugzilla Etiquette] * [https://bugzilla.mozilla.org/page.cgi?id=voting.html Voting] * https://bugzilla.mozilla.org/show_bug.cgi?id=1149972