Macbook icons and menu bar not showing during Teams screenshare

This feels like it should be a common thing, but I can't find the answer anywhere.

I'm using Teams (on a Windows PC) to hold a video call with a MacBook user. When they share their screen, I can see everything as expected, except for the menu bar across the top, and the icon bar across the bottom. This is making it difficult for me to instruct them on what they need to click on, and for me to see the results.

Is there a setting that needs to be adjusted at their end or mine? If it is their end, is is an Apple setting, or something in Teams?

Many thanks in advance.