How to remove onscreen flag during screenshare

Hello,

When I screenshare, this flag stays on the screen:

It really interferes with my ability to maneuver during a screenshare. I can't dismiss it - I can only move it around on the screen, and it blocks whatever's behind it. I can't shrink it. Wherever I move it, I eventually have to move it again when I need to access that part of the screen.

There has to be a way to turn this off... I know I'm missing something obvious :) thanks for your help!