Hey, I’ve had something similar happen. A few things that helped me: try updating Firefox to the latest version, and also disable any extensions one by one to see if one of them is causing the sidebar to freeze. Sometimes restarting in Safe Mode (without extensions) can help figure out the culprit. Hopefully that helps!

Thanks for your suggestions, I will try them. I appreciate the help and that was quick!

I disabled one extension and that didn't help, but the next time it happened I had a light bulb and I found this to work: I went to settings (general) and unchecked the "show sidebar" and then checked it back. That took care of it.