This is so damn close to perfect that it makes me want to cry, seriously! I'm running multiple (let's just call them 'large' monitors) and when Firefox constantly opens up its browser windows in what appears to be relatively small windows, this app is a welcomed relief. Here's why it didn't make 5 stars. Perhaps I missed it in the opening instructions and me not getting 8 hours of sleep in the last 3 days has taken me down a couple of notches, so if I did miss it, I apologize Juraj. But I wish there was a way the program could automatically detect if it was connected to a multi-monitor system. It it was, then it would remember to automatically open Firefox in the same size and position that it did last time it was. If not, it would default to the Firefox standard way of doing things. Opposed to having to reset the window size every time you completely shut down Firefox. Otherwise I completely love this app and can't understand why so few people haven't stumbled upon it. It's genius!