I released a new '1.1' version that should fix this. Please follow this link to see how to update firefox extensions https://support.mozilla.org/en-US/kb/how-update-add-ons

Thanks!

EDIT: I am sorry to hear you are having issues, as I am using versions 1.1 of the extension with no problems. Maybe try uninstalling and reinstalling again? You can also download a previous version, which will also verify if the new version really doesn't work for you right now ) :