Notice the bottom of the unity bar. That is where the bottom of the that monitor is (I'm using twinview, so you can see the beginning of the right monitor where you can see the wallpaper, on the left screen thunderbird is running maximized)
Notice the bottom of the unity bar. That is where the bottom of the that monitor is (I'm using twinview, so you can see the beginning of the right monitor where you can see the wallpaper, on the left screen thunderbird is running maximized)