I'm running Firefox 71 on Linux. I notice that when I load a page into a new tab (either from middle-clicking links, or entering URL manually), Firefox UI is unresponsive for about 2 seconds. During that time, I'm unable to switch tabs--either by clicking, or with Ctrl+Tab. I tried restarting with all add-ons disabled, but the problem persists. The problem disappears if i were to create a new temporary profile, though. So it's clear that something in my current profile is screwed up, but not sure what. Other things I've tried: quit Firefox, I vacuumed all `.sqlite` files in my profile; cleaned up all the cached images (not site data, though). I'm keen to continue using my profile rather than create and setup a new one. Any help to trouble shoot this problem is appreciated. Thanks.