After the IFC import DIALux creates spaces in every shaft and void, which can never be a space. Is there a way to remove those extra spaces?

Further DIALux creates two or more spaces, where is actually only one single space. It seems to pick up different floor levels and create spaces based on that, whether there is a wall or not. Is it possible to combine those spaces after the import? My work-around is that I give the failed spaces a very short name "." to have the annoying annotations out of the way and create new spaces on top of the old ones.