f9.hell-labs.net##.quickbuttons [id^="quoteSelected"]
maybe there's a better answer to this. i tend to highlight text sporadically while i'm reading it so i don't lose my place, and this button flicking in and out of existence while i'm doing so was extremely annoying. maybe it could be made to only appear if you hover over the quote button while you have text selected? (i haven't looked too close but i wouldn't be surprised if this could be achieved purely by adding a couple css rules)
We could in theory replicate the behavior of the "More..." button, where it provides a menu if you have text selected. I'm not sure that's great from a UX perspective, though.