While it's running it seems smooth and efficient, or at least not a bear like Ghostery. It's something with startup. Anyway, minor nit, it's a great extension.
It looks like another addon was phoning home to a blocked resource. I should've tried more combinations first. The best thing I can think of is that it would be cool if uBlock reported when a call from another extension has been blocked.
> it would be cool if uBlock reported when a call from another extension has been blocked
That is the purpose of the built-in logger[1]. By default uBO is not setup to block other extensions' network requests, or those made by the browser itself, one has to configure it explicitly for this to happen[2].
That's bizarre! Have you tried disabling everything except uBlock and seeing if that persists? Maybe it's some kind of interaction with other addons causing the problem.
Another user recommended uMatrix as a Ghostery replacement in this thread which I was trying out, and it looks like some Ghostery/uBlock interaction was to blame. My best guess is some Ghostery resource is correctly flagged by uBlock and that the delay I experienced was a request timeout or similar, from Ghostery.
Maybe it is interaction between it and another addon. I just removed and reinstalled all my addons last week and performance was dramatically increased.
Well, not all my addons - turns out though my Scriptish has been installed since Firefox 3 (now at 45), it wouldn't reinstall after removal for compatibility problems. Not sure why that wasn't automatically detected, and that may have been the performance issue
That's even what they show in the chrome/firefox store images, it doesn't make much sense to me that it adds several seconds to Firefox startup time
Am I missing something ?