I am completely new to DSM so please bear with me!
I am trying to design a very simple case for a small electronic device: Essentially a "box" with rounded corners with a front side that has one hole for a potentiometer, the rear side has several rows of holes for ventilation. There is certainly more to come but that's how far I am by now.
While replicating the rear-holes and adjusting them to be evenly spaced across the back plane I somehow managed to remove the actual backside. I.e. the rear-side consists of those holes but there seems to be no more material around them. When I spin the box the holes seem to hang in "empty space". I tried to make that visible in the attached screenshots.
How do I "re-attach" that side to the box again (while preserving the holes that is). Or maybe I just made it invisible? But how do I then make it visible again? Hope I could make myself clear...