SKelevra

I understand that and believe you may have misunderstood the intention. The effect this has is the issue in the thread, so if for some reason they aren't connected, you will get this issue as a result. Be it from your initial connection or by some errer of removal. So it may not be this persons specific problem, but it IS a response to the problem.

So, I was having this issue for a bit, and I apologize if this answer has been given before, but: When you are attaching a door or a window to a wall, make sure you your not just sticking it to the wall and are instead placing it into the wall. (Sounds similar I know, screwed me a bunch early) The first will only highlight the wall in gray, the second will select the wall in red like truss when you attach a light to it. (Also make sure your wall isn't locked, or it won't grab it)