Does anyone know what the difference is between an assembly that I can drag and drop another instance of a part from the browser into the assembly and one that I can't do the same? I have an assembly I've been working on for some time and it won't allow me to drag and drop or copy and paste instances of parts. If I start another new assembly and place several of those same parts in it I can drag and drop and copy and paste without problem. Is there a switch or setting that needs to be changed in order for this powerful and better way of populating an assembly? Thanks.

Inventor 2013