Newbie - Need Annotation Help

Hi, total newbie here on this software.

i am looking to annotate CT scans, bone fractures specifically, and I need to mark / annotate the CT scans for the data people. I need to make a minimal rectangle/square around the fracture site.

when I go into segment editor and set up a new+ and name it and color code it and use any of the marking tools ie paint brush or the pencil connect-the-dots method, when I completely mark the fracture and right click to finish, it disappears

I tried double left click, right click, a, enter, all the same result. And the annotation marked out just disappears. So I can’t even save the annotation with the marking I need

what am I doing wrong?