• 2D Follow up: Add dual scrollbar constructors and methods #122348
  • will need to be completed first

Part of the 2D scrolling proposal: flutter.dev/go/2D-Foundation

#122349 adds a factory constructor that creates two scrollbars for scrolling in two dimensions. This change is proposed as a lead up to TwoDimensionalScrollable etc.

Developers may want to configure dual scrollbars so that the fade in animation is always triggered for both scrollbars in response to any scrolling, or just one axis, or none, etc. It is not clear yet how folks may want the animation to behave, but we should follow up on it here when it becomes more clear.