I'm creating objects by using ArchiCAD tools, I can create the shape but there's many unnecessary hotspots when I select object. I don't know how to delete / hide them ?
Yes, the custom object that embeds hotspots into the new user-defined object needs to remain in the embedded or linked library in order for the hotspots to remain active. Otherwise, there will be the usual missing object message.
I suppose if you save the new object as a binary (can you still do that any more? I haven't done it for years...) then it might not require that, but of course it would make the new object a lot less configurable.