Oooo! I found a way to keep it off my screen, sort of. If I hit the "X" that stops the browser from loading the page before the notification pops up, it won't pop up. This is great for viewing "Recent Posts," though I haven't tried it on an actual
thread (I suspect I won't get pictures loaded before the pop-up) or when making a reply (which might not work because the page won't be loaded completely). But, I'm willing to sacrifice pictures to not have a pop-up...