I recently switched over to a dual monitor setup and am still getting to know the features. I've noticed that whenever I mouse over from a game onto a browser (Chrome) and clicked, it would minimize the game from my primary monitor (the browser being opened on my secondary monitor). This is very annoying and I can't figure out a way to fix this.
This only happens if you run a game in full screen mode.
If you go to options => graphics in this particular game and turn the display to windowed / borderless, it'll solve your problem.
Then the game will stay open in the background, while you can manage other programs (e.g. Chrome) and turn back to the game afterwards.
Note that if you use your mouse to scroll than this won't be a problem, most games lock the mouse to their "windowed fullscreen".
Try it out and I hope you succeed.