User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:85.0) Gecko/20100101 Firefox/85.0

Steps to reproduce:

You can not do ctrl+c and ctrl+v on a message in drafts folder. This way you cannot quickly copy the message a few times, if you have to write the same to a few people

Actual results:

nothing

Expected results:

get a message

Could you be more specific about the steps to reproduce?

The messages in the Drafts folder are closed, not open for editing?

Works for with the messages open for editing.

Copy from the closed Draft message works, but the other message needs to be open for editing.

You could add all the email addresses to the message you are copying from as To:, Cc: or Bcc: so you don't have to create multiple messages with the same content.

If you want to write the same message multiple times, you can save a template instead of a draft. Or, right click on any existing message and pick "edit as new".

But, your request as stated is bug 512942