kirill,
Thanks for your response, the problem is that the plugin only appears in the first file of a session, be it opening Sketchup with an old file or a new one. If I open an old or new after the initial startup, plugin is simply not there, curves or curves/faces selected doesn't make any difference( works both ways in first file opened).
The strange behavior is that the plugin follows the copy/paste and works on the original object (even though I have deleted it after pasting) in the new file but not on anything newly drawn.
Actually by thinking out loud I can see now how to do what I need to, just a cumbersome path.
The plugin, itself, has a nice feel.