The thing about the clipboard has been around since the beginning of Excel. I thought I had read an article about it by Joel Spolsky years ago but all I could find now was a quote by Joel answering a question on a forum. A superuser comment quoted Joel as an answer [1]. The archive link for the original discussion is here [2].

[1] https://superuser.com/questions/611854/prevent-excel-from-cl...

[2] https://web.archive.org/web/20160725070440/http://discuss.fo...