From the help file:
Allow copying to clipboard even when not editing
When this option is set, you can mark blocks of text and copy them to the clipboard (see Edit > Copy) even when you are not currently editing a record. This option is turned off by default, because it is easy to mark small blocks of text by accident when clicking on records with the mouse (if you drag the mouse slightly while clicking it), and the result can look rather confusing. But if you don't think this will be a problem for you, and you need to be able to copy to the clipboard when not editing, then turn this option on.
This option should be available under the General tab in the Tools - Options / menu according to the help file, but is missing in version 3 Build 4408. Was also missing in Build 4406.
This was a very useful option. Where has it gone?