Firefox recently updated to 89.0 (64 bit) and now sometimes locks up

As the title says. I sometimes have two windows open, one playing videos on youtube and another where I am doing other things. And then it locks up. I can't do anything, the x button won't close it, the mouse can move around but that's about it. Eventually Ubuntu asks me if I want to wait or force close, so I force close.

Anyone else had this issue or know what is causing it?

You can see what is going on behind the scenes in Firefox by accessing the Firefox Task Manager

This can be done simply and quickly by typing about:performance in the address bar

Once there you can see what the resource usage is, expand tabs to see trackers and to close tabs as required to identify any issues.

The Task Manager will allow you to identify rogue scripts and take appropriate action in identying any issues.

reference

If necessary, Firefox can be opened in safe mode: in terminal firefox -safe-mode but first make sure to close any Firefox instance before running this command.