This has been bugging me ever since I got my first Mac in 2011: applications sometimes automatically toggle the "keep in dock" setting for themselves. I suspect this happens for applications that I use often, but I'm not sure and I can't consistently get it to happen. I like to use my dock for currently running applications, not as an application launcher (that's what Spotlight is for!). I want applications to leave the dock when I close them. Has anyone else noticed this, and is there a way to prevent it from happening?