I have found the only way to avoid the disconnect is like this.
Character B will be following A. (character B is twink character etc and character A is your main char)
1. Login Character B
2. Login Character A
3. Go to Video options and both of them and set it to WINDOWED MODE but NOT maximized
4. Focus on Character B's Window (Click on it in the task bar, so you can move around in it etc).. Click Character A and click FOLLOW.
5. Focus on character A's Window, enjoy and you will not disconnected if you followed everything.
notes: If you focus on another window that is not wow.exe (world of warcraft) Character B WILL get disconnected.
to avoid this when you want to open browser (for searching items etc on wowhead or another site)
OptionalStep1. Click on Character B , stop following
OptionalStep2. Open up internet browser..
Its that simple and that should avoid annoying disconnect. then just repeat the steps 1-5
(is this the right place to post this?)