Discovered when leaving phpsysinfo tab open continuously in firefox 4 beta. After some time, any request to the server produces error 400 "Size of a header field exceeds server limit". The long header field is a cookie created by jQTreeTable.
The problem is jQTreeTable tries to use jQuery.unique to produce an array of unique numbers, but the jQuery documentation explicitly states "Note that this only works on arrays of DOM elements, not strings or numbers." - because this doesn't behave as intended, the cookie strings just get longer and longer with more duplicates after every reload.
Please find attached a fix to this issue.