As the title/subject said, this is what I just spotted today.
In short:
if/when facebook window is visible: no issue
if/when facebook window is NOT visible: eats ALL RAM
Long version:
I am using an old Logitech G15 with the LCD display set up to show temps and other system stats. I just had the facebook messages open in one window on the left and a youtube video playing on the right in another window. I have enabled the full screen mode on the YT vid, put my headset on and did chores while listening to a podcast.
I came back to the PC after about 30 mins and the LCD on the keyboard was showing a red bar for the memory that got my attention. ALL of my 32GBs of ram was used up by something. Did some playing around closed tabs, restored them to try to replicate the issue.
After some time I have reduced my tab count to just having FB on left and YT on the right.
What I found was that if I cover the facebook window with anything (note pad, a folder, whatever to block it so that the window is not visible at all), it will start consuming RAM bit by bit. With 10-50MB increments it gradually hogs all the available memory (32gigs in my case).
If I reduce the size of the window (note pad) that is covering the FB one, it immediately dumps the RAM use down to normal (6-7GB of the 32 available). Even if it is just a couple pixels of the FB window visible, this happens and it won't start reserving more RAM until I fully cover the window again.
Minimizing the window has the same outcome, continously consuming RAM until all is gone.
Running Win 10 and Mozilla 112.0.1
Timelapse
https://youtu.be/Wb2ZvUT24rQ
