Replace Window::scrolling_scrollbar with Window::mouse_capture_widget #7227
This allows us to support generic widget scrolling/dragging. Scrollbars are now handled by testing that the widget type is
This is followed up by setting
And for completeness, click-left dragging the smallmap is improved (and matches right-click dragging behaviour) by setting
…ispatch OnClick() event if widget is not a scrollbar. This allows any widget to support mouse capture.
This makes the slider continue to respond even when mouse cursor is no longer over the widget.