OS X app that works without being active?

cocoa, macos

Solution

I believe these types of apps use `LSBackgroundOnly` or `LSUIElement` as Launch Services keys in their plist files (reference).

Here's a bit more about it.

Problem

Recently i've tried ColorSnapper app, and I've noticed that it works keeping other applications active. (Check the screen below, as you can see safari window is still active and ColorSnapper keeps being active too). How can is possible reproduce this effect ?

Original source