Feature #1704: Focus-window selection in cartesian charts
Focus-window should be controllable by a separate scroll-bar-like control
A scroll-bar control, aligned along the focus-window domain axis, possibly placed after the axis-panel, or its associated title panel, in the outside direction, would allow moving and resizing the focus window.
This control exposes visually the interactions that are possible with the focus-window.
When this control would be visible, it should be possible to disable the default mouse/keyboard controls.