Accidently copying one file metadata to all songs

I am still not sure how I did it, but somehow I copied the metadata from one song to all the other songs in the directory. I did not get a prompt to confirm the copy/overwrite. I tend to use the keyboard short cuts, so control+c and control+v to copy the metadata from one song to another, F4 and F5.
I cannot confirm when it happened the first time as it took me a while to look at that directory again. It happened one more time and I do not know what keystrokes I used to do it, but I do remember that I did not have all the files selected. The second time I was able just to do a control+z and it undid my mistake. I wish I could give you a better idea of how I did it.

If you want to copy the metadata from the selected file to one or more other files you would do exactly this:
Press CTRL+C on the source file (with the metadata you want to copy)
and then
select one or more target files and press CTRL+V to paste this metadata from the clipboard.

There is no warning message until you set it in File** -> Options -> Messages (press CTRL+ O)
For example "Show message at pasting tags" before you paste it or "Show message after change" to show a hint after pasting.

** Valid since Mp3tag v3.19. In previous versions it was File -> Options -> Messages.

According the help the keys work like this in the Mp3tag file list modus:
F4 Play selected file(s)

F5 Refresh

So none of them should copy and/or paste anyhting between files.

I was just giving the keyboard shortcuts that I usually use. The effect of what happened would be
select one song
control c
select all the song
control a
update the metadata on all the songs
control v

It is just that I am pretty sure that I did not do the control a bit

I suggest:
Check/Activate the two messages mentionend above and you will be warned next time you accidently press such a combination.