Prevent Zoom going to fullscreen mode when remote user begins sharing?

I've been in Zoom meetings where a remote user begins sharing their screen and it causes the meeting to go into fullscreen mode on my computer.  I don't want that to happen.  The meeting should stay in a window until I decide to go to fullscreen mode.  It didn't used to do this, but I see this happen now when I started using Zoom on a new computer.

How can I prevent Zoom from automatically going to fullscreen mode?

Looking at the Zoom "Settings" window, under the "Share Screen" section, I see an option for "Window size when screen sharing".  It has the choices "Fullscreen mode", "Maximize window", and "Maintain current size".  It's unclear to me whether this applies to when I begin sharing, when the remote user begins sharing, or both.