Apturize your browser!
Apture plugin with a browser button.
Why you'd want it. It's like the Apture Highlights extension, but with a button to toggle the search bar.
Why you wouldn't want it:
I originally posted this extension before Apture officially announced their own Apture plugin - Apture Highlights. I recommend that extension instead now, because it's actually nicer and works better with some websites. However, I'll keep it up here for a bit longer in case anyone has linked to it.