Remove rectangle spoiler when fastforwarding

[Freezard]

So I've removed all kinds of stuff, as I want nothing on the screen except for the video. But when I fastforward during fullscreen, I still get a rectangle showing 'my position' in the video (eg the video is 1 minute, I fastforward 30 seconds and it will show a vertical line in the middle of the rectangle). It's not there when I get out of fullscreen though.

Any way to remove this?