User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:65.0) Gecko/20100101 Firefox/65.0 Steps to reproduce: 2. go to https://www.youtube.com/watch?v=brJ-QBtRvRk . Start playing the video. Forward to a few minutes so that enough live comments are loaded. 3. Enable the live chat panel/sidebar 4. Now keep on win aero snapping the youtube window in the following order : left, top,right,top,left and so on. OR keep on resizing the window such that the livechat sidebar will reflow to the bottom, or side of the screen 5. Each time you do it, the live chat will reload. Let it reload each time. Actual results: Each time the livebar reloads, the memory will increase. This increased memory does not release if you do "minimize memory" Expected results: not so?

FWIW, most of the memory is in strings, window, and JS runtime. The gfx part I think would be bug 1509656

335.69 MB (28.55%) -- top(none)/detached Does Youtube end up removing iframes and adding new ones, yet somehow keep references to the old iframes. (wouldn't be the first time a Google web site does that.)

memory report with a new profile, no addons, and not even signed into google/youtube. So should have lesser noise,