Author: Jonas Bilinkevicius 

I have been trying all day to keep a descendant of TRichEdit from copying/ cutting 
to the clipboard with the use of the [ctrl] +[c] and [ctrl] + [x] keyboard 
shortcuts with no luck at all.

Answer:

Try a different approach: to copy something there has to be a selection, otherwise 
there is nothing to copy. So attach a handler to the controls OnSelectionChange 
event. This handler contains the line:

1   with Sender as TRichEdit do
2     SelLength := 0;