User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:54.0) Gecko/20100101 Firefox/54.0 Build ID: 20170608105825 Steps to reproduce: 1. Open Run window 2. in Run prompt enter: "C:\Program Files\Mozilla Firefox\firefox.exe" http://sailorjerry.com/en/harley-davidson/ 3. Click OK Actual results: Firefox opens page. AdBlock add-on should block some elements on page and Roboform add-on should open pop-up window. They DON'T. When you open second tab or click "Reload", add-ons start work as expected. Expected results: Looks like some add-ons aren't activated when running Firefox from command prompt. It is not issue of add-ons, because two different add-ons started to show similar behavior at same time, with same Firefox build.

P.S. Tried many web pages - they would have same problem. Like: "C:\Program Files\Mozilla Firefox\firefox.exe" http://www.facebook.com

Andy, not sure what team should own diagnosis/triage of this, but I'm throwing it to you first. If this doesn't affect webextensions it's perhaps less important, but this is the kind of startup ordering regression that may be worth an automated test in either case, since this startup path is one that's hit frequently by a class of users that doesn't keep Firefox open all the time but opens external links.

There's a few more bugs on this, so I'm rounding them all up and blocking them on that other bug.