Delayed rescaling when moving from 1x scale monitor to higher scale monitor

When moving a window from a screen to another one with a higher scale, the whole window is "blurred", as if it had been rendered to a texture with a lower resolution and then scaled up. This only happens if the window is partially still on the screen with the lower scale, so not anymore if the whole window has been moved to the other screen.

A bit of context, this doesn't seem to be a bug in my compositor. `winit` (a window initialization library) used in another program reports that the scale factor changes to 2 once any part of the window is visible on the high scale screen (with the window size doubling), and reports the scale factor changes to 1 once no part of the window is visible on the high scale screen anymore (with the window size halving).