src/vs/editor/browser/controller/mouseTarget.ts/MouseTargetFactory/_hitTestScrollbar
class MouseTargetFactory:	private static _hitTestScrollbar(ctx: HitTestContext, request: ResolvedHitTestRequest): IMouseTarget | null {
		// Is it the overview ruler?
		// Is it a child of the scrollable element?
		if (ElementPath.isChildOfScrollableElement(request.targetPath)) {
			const possibleLineNumber = ctx.getLineNumberAtVerticalOffset(request.mouseVerticalOffset);
			const maxColumn = ctx.viewModel.getLineMaxColumn(possibleLineNumber);
			return request.fulfillScrollbar(new Position(possibleLineNumber, maxColumn));
		}

		return null;
	}