All other copy to clipboard action are `alert` free like copying a table name to the clipboard. I think it should be the same for copying a column value.
If you think some feedback is necessary, maybe we should see a small label showing up than closing shortly after. As a comparison, it appears GitHub, in the commit list view, does not shot any feedback anymore (is it a bug maybe? because remote url copy still shows a feedback, anyway :)).
P.S. My editor automatically removed some trailing white spaces, if you prefer, I can revert those.
cc1666b16a