As I show you in this tutorial, you can open the clip in Smart Trim in Quick View and trim your clip there.
Look at about 2:30 in the video.
Thanks. I made a mistake. I CAN'T TRIM IN PREVIEW WINDOW, because there are no Set in and Set out buttons (see attached jpg in original post) in Elements 2021.
As I show you in my books, you can use the I and O keys on your keyboard to set the in and out points in the Clip Monitor.