For the login issue it is easy to fix, you make an exception in the privacy settings for whatever website you visit.
It's on Settings -> Privacy and Security -> Manage Exceptions (And make sure you add and Save the Changes).
It's a bit of nuisance at first to do but you only have to do it once, and this way you also have control which websites install their crap on your browser. For the render issues I don't know, it is not my experience but maybe it is related too to make an exception for these websites.
Oh yes it is there, I didn't know that. Thank you!