When I do a single click, my computer (with Ubuntu 12.04) acts like it was double click. I think it happens in ~50% of cases. It happens with all the program I use: browsers, file manager, terminal and so on. I'm not sure when exactly it started, maybe a week ago, and I don't remember if it started to happen after system-update or after the installation of some packages. What I tried: change mouse change mouse settings like Double-Click Timeout None of those helped me. Any ideas? Thanks.