83dbbf9aec
Remove ugly/fragile special case in `view2d_masks()` that would clamp the scrollbar-masks by the scrubbing UI. It's now possible to pass custom scrollbar-masks to `View2D` via `UI_view2d_scrollers_draw()`. So use this instead, making region code control its own masks, rather than relying on special case handling in generic `View2D` code. Also update comment in `scroller_activate_init()` to make the implicit relationship explicit. Alternative to, and based on the investigation in !117685. Pull Request: https://projects.blender.org/blender/blender/pulls/117984