Scrollbar dissapear mid drag if you mouse over away

[alexstyl]

Describe your issue

When I start dragging a scrollbar, the scrollbar must not disapear until I release the drag.

Currently the scrollbar disappears if you move the mouse outside of the track.

Similar note from someone else:

@Alex Styl the problem with unstyled scrollbars is if I hold a scrollbar and don't move a mouse then the scrollbar becames invisible and a scrolling stops.
browser scrollbars don't hide when you hold them