Clip to DevonThink not showing up in FireFox

Just upgraded to DT 2.1 and was delighted to see that there’s a new Clip to DevonThink add-on for FireFox. Unfortunately it’s now showing up anywhere at the top of the FireFox window. [I’m using FireFox 4.] It shows up as installed and enable under /Tools/Add-ons, but it is not showing up, and therefore not usable. What do I need to do to fix this?

You have to customize the toolbar of Firefox.

Thanks, Christian. Didn’t occur to me. Maybe in part because it installed on the Safari toolbar on it’s own.