Thanks for your feedback [:)]

Could that plug-in be integrated in the main program?

It's not what I plan at the moment.

Edition > Paste
Probably this is franglais?

No, I don't think so [:D]
It lets you copy the color/texture of a given copied object on others selected objects of the same kind without displaying again their modification dialog. It can be also used to keep in memory the color/texture of a room for example, when the quickest way to recompute a room is to delete it then recreate it with a double-click. Note that you can copy the style of a room only on rooms, copy the style of a wall only on walls,... and there should be only one object in the clipboard to enable this new menu item.