Thank you both.

Is there a way to turn the preview plane off until I am ready to read mail? While I am deleting what I don't intend to look at it gives me the "I'm busy" spinning circle while it works on changing the display in the preview plane. I think I would rather do without preview totally than put up with the current situation but what I really want is an easy way to turn the feature on and off.

Open the folder in its own window.
Select the folder in the Folder Manager - Press Enter, or Double-Click, or press the Open button.

You should be able to turn Preview Mode on and off by clicking "Preview Mode" on the "Folders" menu.

Jim