You don't. You need to install the Roboform extension for Firefox which is available from Roboform.

Is the RoboForm System Tray / Notification Area icon using IE because IE is your default browser? If Firefox is your default browser and RoboForm still uses IE, it could be a setting in your RoboForm software somewhere.

Edit: Additional thought: If you haven't closed and restart RoboForm since installing Firefox, it might not realize you have installed Firefox.

jscher2000, The default browser is still set to IE 11 so that makes sense. I'm afraid to download another roboform copy using firefox for fear of loosing all logins/safenotes stored in current IE toolbar With all of the compatibility issues in IE 11 I'm finally ready to make the switch...TGCBM

I think RoboForm should include Firefox support without additional downloads, but you could try their support to see how to set it up.