How do I prevent Google Search from spawning instances? I love using the white Google search bar at the top of my home screen, but I only recently discovered that it spawns a new instance for every search I do. My phone was slowing down, and I suddenly noticed I had dozens of past searches in my app switcher. I went through and closed them all, and now my phone is happy again.

Can I have all searches share one instance? Or do I have to clean them up periodically myself? :(
From my own experience of Lollipop, it's Google's new concept to show you everything you're doing as a separate activity. Unless you go down the route of rooting and applying some mod (I don't know of one which does this), the only solution I see is to get into the habit of always closing them as soon as you open them. (Easier said than done, I can say for sure).