I needed Twitter to stop reloading automatically after a tab was inactive for several hours. I did not know that after installing the addon I had to reload the tab for the program to take effect. I assumed that it was not working and I contacted the developer by mail who answered me immediately. And after a few messages he told me that I had to write Twitter.com at the host window and reload the tab for it to work for the first time. And indeed, it worked! Thank you! :D