Found a free tool called Dual Monitor Tools. You can lock the cursor to your main screen when playing older games that do not lock the cursor, even new games do it sometimes. It also allows for 2 different backgrounds on the 2 screens in windows 7. Very useful tool, and for any GOGer with 2 monitors I would say its pretty much essential. Cursor lock is buggy, and does not work as well, or have so many sweet extras. Cheers!

This one?

http://dualmonitortool.sourceforge.net/

Do you know of any portable monitor at 24 inch?

I only found this
http://www.arovia.io/

But the resolution is only 1280 x 720 as reported by
http://www.gizmag.com/spud-pop-up-screen/42350/

That is the one, its very very useful. You can bind the lock to say ctrl+1 or whatever you choose, and holding something can allow free movement between monitors, it is very customizeable. The cursor lock one, every time i would load baldurs gate, it would lock itself on my second monitor till i alt+tab out and back in, then it would work properly.

Its just good. I dont do portable so I wouldnt know. But honestly, anything portable cant be good. Unless it costs a fortune. Just like laptops. To get an actually good one for playing games that require alot of power, you need to purchase an Origin laptop. Which will set you back 2k easy.