Thanks Hans for this nice workaround
I propose that editing inside group would internally ungroup the furniture [...]
storm88, it's not how to program the change of an item that bothers me, but rather ergonomics, to ensure that all users will be able to handle the selection of an item in a group nicely. I wished that you could guess it from the long message I posted this morning. 
(don't worry too much, I wrote it also as reminder for myself)
----------------------------------------
Emmanuel Puybaret, Sweet Home 3D creator
