LyX ⇒ Image "Edit externally" not working in 2.3

[scorwin]

Hi--

I recently upgraded to LyX 2.3.1-1 on Windows 10 and now find that when I right-click a PNG image in LyX and choose "Edit externally...", nothing happens. I do have a system-wide default in place (paint.net) that works fine when I double-click a PNG file in Explorer. I looked around in the lyxrc file but could find no setting for it. Can anyone tell me what to try next?

Thanks,

Steve