Botond, new one from me with the same problem (the original one that I opened this for, not :jcristau's) and a recent build, with the logs you requested: https://share.firefox.dev/49FNPQM. I attempted to scroll in PID 138837 (chat.m.o).
Bug 1877972 Comment 29 Edit History
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Botond, new one from me with the same problem (the original one that I opened this for, not :jcristau's) and a recent build, with the logs you requested: https://share.firefox.dev/48xs7g9. I attempted to scroll in PID 138837 (chat.m.o).