Support mousemove events even when not in browsing mode

[marcofugaro]

It would be great to have some backgrounds that are interactive just with the mousemove events, for example this demo or this one. Or even this one but with the mousemove instead of click.

The mosemove interaction would work always, even when not in browsing mode.

[sindresorhus]

To solve this, we could place a transparent window at the top-most level covering the same frame as the web view, make all events pass through and capture mouse move events, then forward those events to the web view.