User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:64.0) Gecko/20100101 Firefox/64.0 Steps to reproduce: create new profile. Enable WR. Restart 1.Open 2 tabs 1.5 Check RAM usage 2. Click on the "X" button on the top right corner of the window, to close the window 3. A dialogue bow will appear saying something like "Please confirm yiu are about to close 2 tabs" 4.Dont click on yes/ok. Keep this dialogue box open Actual results: Check RAM usage after step 3 It would be increased by ~200MB Expected results: not so

while I have 2 windows. Each has 2 tabs

After I try to close one of the windows by clicking on the "x" button on the top right corner, and a "confirm"dialogue box opens

Thanks for those memory reports Mayank, that's really helpful. It looks like that dialog is triggering the lazy creation of one of the texture caches, which will consume 64 MB of vram straight out of the gate. And up until bug 1496168 landed this weekend, that would actually consume 33% more memory, because of mipmaps. So that explains ~90MB of the regression. It looks like the total increase in committed memory is ~130MB, so there may be something else going on there (I do see the GPU cache growing). But I think we should fix the texture stuff first and then remeasure.

This is much less now if there is only 1 window open. If there are more than 1 windows, the dialogue box uses ~100MB RAM

Can you re-test this for us?

This is much better now. I will close this bug. We can file a new bug if needed in future.