Quote Originally Posted by Khatovar View Post
I think most mouse broadcasting works generally the same across most broadcasters, which is clicking each window in turn in rapid succession. ISBoxer might work differently, but I don't use it so I can't give details on it.
Sounds accurate to me. ISBoxer does work differently and it's a pretty significant technical difference.

Most games "poll" the hardware cursor (e.g. using "GetCursorPos"), which there is only one of. It is impossible for this cursor to be in two places at once (e.g. over one game window AND another), so clicking can only be done in one window at a time by a standard mouse broadcaster.

ISBoxer on the other hand virtualizes the hardware cursor (and the input queue), so there is a cursor per game instance. Therefore, clicking can be done in all windows at the same time, and without activating each window first. The other solutions, by design, cannot do this.