Forcing drag-to-scroll on iframe

I’d like to use Ionic also on desktop. In my app instead of in-app-browser my app opens a modal with iframe when used on desktop browser. I would like the iframe scrolling on desktop to work the way normal Ionic content works in terms of scrolling.

On a mobile device dragging scrolls, but on desktop dragging (with mouse) selects instead of scrolling. This is a problem, because the behavior with iframe content and other parts of the app differ so remarkably.

So how could I apply “mobile scrolling behavior” also to iframe on desktop browsers?