VSE timeline widget drawing is done in "timeline space" (x: frames,
y: channels), but that can have precision issues at large frames,
when "pixel size features" (outlines, borders) need to get evaluated
inside a shader.
This can lead to inconsistent border sizes between neighboring strips,
e.g. sometimes it would be 2 pixels, but sometiems 3 pixels. I've seen
this mostly happen when frames get into 100'000+ range.
To address this, switch timeline widget drawing to be in window pixel
space. This avoids the issue since coordinates to draw the strip
widgets become "up to several thousand" range, not arbitrarily large.
Pull Request: https://projects.blender.org/blender/blender/pulls/125220
527e55239b