Navigate Without Focus?

Hello,

I want to be able to alt-tab to another program, or have a second program that's the focus, with Unity running in the background. I was wondering how/if this would be possible?

I've done the "Run in Background" flag check already.

Thanks!

(THIS IS A REPOST OF ANOTHER QUESTION I CLOSED DUE TO A LACK OF AN ANSWER WITHIN A DECENT TIMEFRAME).