Apple mail preview pane missing
I do not have a preview pane in Mail any more.
In Catalina 10.15.7
It is not at the side, and does not appear however the \View\use side preview drop-down is ticked. dragging the sides of the wind has no effect.
If I follow forum instructions and try mail\Preferences\Viewing\ use classic layout (box ticked) I am hampered by there being no "use classic layout" option in my Mail preferences, or any other mail menu.
I know that Apple changed Mail to put the preview at the side, but it has been completely removed from my iMac.
Has anybody any suggestion how I can unbreak Mail?
Ta
Frank
iMac Line (2012 and Later)