Plenum space question

[Secttor]

Hi.

I have the folowing scenario : 4 walls, room bounding set everywhere. 

1. place a space on Level 1 ok

2. create a new level for ceiling (set to Building Story - what's for?) and a ceiling on it. 

3. going on the Plenum View (earlier created) and try to create a plenum space.

4. receive this error but space is added. 

Which is the reason for receiving this error? does the new space is properly added? 

Thanks!

[debimmanager]

Yo have to check the upper limit, and limited offset relates about your spaces in properties palletes. The plenum space makes an overlap with space on level 1. You can check it selecting a space