Unruly question

I'm trying to write a win32 platform layer for the first time (I've mostly written software for linux).

It seems that remedy is the only program on my computer that maximizes instantly. In other software (mine included), there is ~1+ frames where the framebuffer looks old. I've attached a video.

How did you do it?

My program has a synchronous WM_PAINT render pipeline for smooth resizing, but it seems that isn't good enough.

2023-01-02 02-00-43.mp4