If you check the Extensions button drop-down, is Roboform listed there? All the extensions Firefox recognizes as enabled should appear either there or, if you pin the extension to the toolbar, on the toolbar.

Ref. Manage your extensions using the extensions button in the toolbar

It works for me.

Do a clean reinstall of the extension by removing it, refreshing the addons page or restart the browser (necessary to clear settings), then reinstall it.

I have done all of the above. Still does not work. I am attaching screenshots. There is something missing in the new release with firefox to allow this to work.