Problem that I have is with Firefox (Dev Edition 55) and multiple web extensions add-ons (Roboform, AdBlock, etc.). Say, I'm opening some page in Firefox from external link, for example: https://www.facebook.com/themeltingpotrestaurants/photos/a.263404988027.142147.45664163027/10155538922443028/ Page opens, however, neither Roboform nor AdBlock is active. Next step - I'm opening SAME Facebook page in new tab of same Firefox. Now Roboform and AdBlock work ! I feel that there is some latency in activation of web extensions in Firefox. So, to use them, I have to open page, wait some seconds, then open same page again in new tab.