Sometimes there is returned "400 Bad request" error when I try to attach a file on the our Trac(http://trac.edgewall.org/). At the same time I can do it in the IE and Chrome from the same machine. Problem appears from time to time. So not sure, that this is Trac's problem. Or maybe it is) I am using Firefox for 4 month to work with it, and problem started to appear maybe a month ago, not sure from what version of Firefox exactly. If there is necessity for additional information or logs, please let me know were are they placed in the Firefox and I will add them. Thank you.