This is a very minor irritant (at least for me.) Every once in a while, I'll start to add an object to a scene, and then realize I need to cancel (I suddenly remember that the object isn't ready or some other reason.) But then the warning "ObjectLoader: No object file specified Obj reader 01" comes up when I click cancel and adds "Obj reader 0x" to the objects list. I think, of course "no object file specified", I canceled the request. This happens with all the "readers" (at least in the "Add Object" section.) And if I don't delete those "empty object readers", they come up as warning the next time I load that tgd.
Anyway, does that message/warning on a cancel really serve any purpose?