I thought this “line width” was intended to only affect lines in the 3D editor? With it changing everything it makes it more complex to determine how big something is since this is independent of user scale. We currently have a very large number of unnoticed “off by a pixel” errors because of this.

For an example think about having to know the width of a some widget. Without line-width it is trivial to just work in ui_widget_units since these are changed with user scale. But adding line width makes the calculation complex since it depends on how many borders it has. You might have a user scale of 1.5 and thick lines or 2.0 and thin lines. Yikes.

The cause of this is a bit complex. I have more detailed information about it, and a patch that corrects, it here https://developer.blender.org/D4947

But because of the complexity of the underlying problem my changes are fairly drastic, which makes it less likely to be accepted. I was just unable to find a quick and simple solution that worked good enough.

@Harley Acheson (harley) Will leave this one to you to classify.

Since this is not really a bug, more of a usability issue, I'm setting this to "Known Issue". I intent to look at Harley's patch soon.

Indeed, @Harley Acheson (harley) already solved this problem a long time ago. We just need to merge his changes and we are golden.

Don’t get too excited. My patch is only useful if someone (smarter) refactors the corner-drawing. https://developer.blender.org/D4947

This was fixed with this commit: https://developer.blender.org/rB4e8693ffcddbe580ddac21e305a085dd846a6c04