Child space divider widget(s) for horizontal and vertical division

[WeirdConstructor]

The desired functionality is:

• A container widget for 2 children
• Either with horizontal or vertical layout
• In the center is a handle or "slider", that the user can hover the mouse over.
  • If possible: Change mouse cursor shape.
  • Have a :hovered attribute for responsive styling
• It should make the position of the handle set- and get-able, best also emit some kind of event or callback when it changes.
  • Usecase: The user can setup his desired layout,
    and store the positions in some external save format. And later reload their project with the sliders
    at the original position.

Like demonstrated in Blender in this screencast:

Kazam_screencast_00066_up.mp4