Lately, the proxy authentication dialog keeps popping up every now and then. This is incredibly annoying: even though my credentials are remembered, I still have to click OK, sometimes a few times before I can proceed viewing the website. Sometime the dialog from a website on a different (background) tab pops up and disturbs me while viewing another website. My setup is as follows: Currently, I'm using Firefox 31.0 on openSUSE 13.1 I have a cntlm proxy set up and set as my system's proxy (http_proxy and KDE's proxy settings) at http://localhost:3128 which works correctly in other applications. I tried using two settings in FF: 'Use system proxy settings' and 'Manual proxy configuration'. I tried both, checking and unchecking 'Do not prompt for authentication if password is saved' I tried a suggestion from the web, setting signon.autologin.proxy to true. I tried some proxy addon which promised to solve the issue. None of these worked in preventing that incredibly annoying proxy authentication dialog from poppin g up (although, at times it *seemed* that I didn't get if for a longer time (that was after making the about:config modification mentioned above)). I remember times on this machine when that did not happen, but I can't remember what I've changed that it's broken now (probably it was some FF update?). Please, help me! I'm lost and it makes my FF very uncomfortable to use. I need some suggestions on how to configure FF in a way that *should* work, i.e. which combinations of the settings I mentioned above, or other ones I haven't considered yet.