I start with 1 window. I split the window to show 2 buffers. I drag one buffer to my other monitor and...
On B6 under Ubuntu I get the following behavior:
...it opens a new window back on the first monitor that doesn't have the minimize/maximize buttons. I can drag this window to the other monitor and manually resize it.
If I try the same with 18.0.1.2 on Ubuntu, 18.0.1.2 on Windows, or B6 on Windows it works as follows:
...it opens a new window where I release the mouse that has minimize/maximize buttons.