Problems with multiple displays

We have been trying the use the multi monitor features but have run into a few problems.

We're trying to get one window to open on the primary monitor, and one on the secondary monitor. It seems to work fine on the desktops we've tested on, but hasn't worked on a variety of laptops (tested on three plus different laptops). What happens on laptops (with a monitor attached) is either:

• The windows open on the same monitor (with one in front of the other).
• The windows open on separate screens, but clicking any window instantly minimizes the other

Details:
Tested on Unity 5.3.x, and in 5.4 beta with the same results.
Tested on Dell laptops (LATITUDE E6410 and E6420)

Any solutions or information appreciated.

Thanks!

Also we'd also like to know if there's a way to switch back to a single monitor after entering dual screen mode.

 

It prints 2. The second monitor is connected with VGA.