Problem

If the geometry of your building model has been compromised due to an error, or invalid geometry, you may find that surface elements have become detached from their parent room.

Should deleting the room via the project tree not remove these elements, you can do so as shown below.

Solution

The steps demonstrated in the below video are as follows:

1. Enable the Properties menu
2. Select the element(s) (left click on the element with mouse)
3. Change to unlocked in properties
4. Left click on element
5. Press delete on keyboard