"Missing Curtain Panels will be replaced with System Panels to complete command."

[ktracy.194130]

I am editing a group and whenever I hit finish I get the message "Missing Curtain Panels will be replaced with System Panels to complete command."

Does anyone know what this means?

[d.stairmand]

I have come across it a few times - for me its either
A] You deleted a Curtain Wall Panel by Mistake - you need to swap to "Empty" or
B] You have added in a Non System Panel & have edited the Border to a Weird Shape - Which Non System Panels cannot fit within - It then automatically swaps the Non System Panels for System Panels to complete the Borders