How to maximise google maps and YouTube videos

Hi, I sometimes have Google maps minimised in the corner of my phone screen of my S7 Edge. Until recently, if I wanted to maximise maps I could just touch the minimised map and icons to either maximise or close it would appear. I tapped on the maximise and it again filled the whole screen.

Recently when I minimised Google maps and tapped on the tiny minimised rectangle, the maximise and close icons did not appear. So to maximise the screen I now need to return to home page and open Google maps again from there, which is very cumbersome (especially if driving).

The same is true of YouTube videos. Does anyone know how to get the maximise icon back on the minimised screen in the corner of the main phone screen?

Many thanks