Diễn đàn hỗ trợ Firefox

This started a week or two ago intermittantly on some websites. Today I cannot see any images of amazon items in the shopping cart. I can see the thumbnails in the right side bar, and if I click on an item, the image appears on its for sale page. Ebay usually shows the first image, but the rest won't load, unless I click on "unable to load images" and then they might. Or if I use the icon to put the images in their own box, I can < and > to navigate them

Turned the new "secure DNS" feature off & on, no difference. Turned off NoScript, no difference.

Today, it started.

When I open sites that I am subscribed to, a small gray-shaded nearly transparent rectangular window appears in the upper right of the screen (see attached screen capture), and it blocks access to login and search, thus rendering the site inoperable. The latest site rendered inoperable is Amazon shopping, so this is not a minor thing. I can no longer retain Firefox as my default browser.

No other browser on my Mac does this; the earlier version of Firefox active last night did not do so either. What is the purpose of this gray-shaded window? It makes the latest browser appear to be infected with malware.

Running OSX 10.13.6 on a mid 2012 Macbook Pro.

'When I try to sign in to Facebook on my laptop, it says that I am using the wrong password. But that password works for Facebook on my iPad and my iPhone. I'm wondering whether simply changing the password is a solution or whether this situation indicates something else is going on.