Retain clipboard data upon paste, like every other program in existence.
Normal programs can copy/paste data without the clipboard being cleared, but strangely, Excel is different, inconsistent. Clipboard data should not be cleared upon use (e.g. paste).
Gregory Appel commented
Hi, can you describe the scenario in which clipboard data is cleared upon use?
I can't seem to be able to reproduce it.
Agreed! I'd vote for this, but there are so many other problems with Excel Online that I've already used them up.