With kwin_wayland using the i915 driver on my i7-3537U iGPU, I get tearing in the Plasma panel if I move my cursor too quickly from multiple panel elements at the same time. The Application Menu widget, for example: I open it, and rapidly move my mouse over all the categories constantly. I see occasional tearing because it can't keep up, and if I keep it up for long enough, plasmashell **** itself and crashes.

Is this a kwin_wayland issue? Is atomic modesetting required to solve this? Is it because Plasmashell uses QPainter? What's missing to make "every frame is perfect" on kwin_wayland?