Copy paste not working

One really useful editing trick for removing a click is to copy the wave form immediately before it and paste it over the click. But in 9.5 this doesn’t seem to work - you can copy to clipboard, but the paste special options (where you get Overwrite) are greyed out and not available. Any ideas? I’m sure it used to work…

It works ok with Wavelab 9.5.40 on Windows 10 here, if we’re talking about the same thing. Edit tab, “copy” button, “paste” button - select Overwrite. None of the paste selections are greyed out. Audio file, not montage, right?