How to determine why a page is always shown as loading?

Question

Mozilla Firefox

At the moment, the pages of the lenta.ru projects (tape, medical portal, sports, etc.) show an "incomplete" loading - the trobber rotates all the time, although the pages visually completely loaded. The status reads Read facebook/rambler/vk/hypercomment/etc - pages of social buttons, comments, etc. With disabled AdBlock, there is no such effect. Browsing in the built-in inspector and profiler doesn't show anything "loading". How to catch the reason?

Answer 1

Social networks got into the Adblock filter. That's the reason. Perhaps he considers them banners and he is stuck somewhere.