Desktop Window Manager High CPU and Delayed Window Movement

Hate to necro the thread but this is happening to me but ONLY with Firefox windows. There is no CPU spiking or delay with any other windows that I drag around. I thought maybe it had to do with the RAM usage from having a ton of Firefox tabs open so opened Chrome and opened the same tabs, using more RAM than Firefox, and absolutely no issue there either. Both have hardware acceleration on too. If adblockers weren't constantly under fire on Chrome I'd switch back but that isn't the case unfortunately.