I'm experiencing this problem when I press Alt+P on my latest map.
What I'm trying to do:
I wanted to make a skybridge, in which a portion of the ceiling and the windows are all breakable glass.
What I did:
In an attempt to make all the glass portions of the skybridge have the same stats, I selected all the windows and the ceiling, right-clicked, and chose "Tie to Entity." From here, I was presented with a window asking me which entity I wanted to keep (all of them were func_breakables, save for the ceiling which was not), with which I chose the first "func_breakable" on the scroll-down menu.
Now, whenever I select either one of the windows or the ceiling, it treats all the glass as one collective entity (ie; as if I had selected all of them). I tried ungrouping, and this did not do anything. On top of this, whenever I looked for problems in the map via Alt + P, I get a boatload of items all saying "Solid Entity (func_breakable) is empty."
Is there any way to solve this? Will I have to redo the glass portions of the skybridge to be?