Using copy/paste in the editor causes glitches especially with too many objects at the same time especially ceilings.
I screwed up one of my maps, copying/pasting a bunch of ud_ceilings at the same time.
I did this 2 months ago and it was the last adds to that specific map.
However I got the glitch now in that map where stuff starts disappearing and then crashes if you try adding more stuff.
Is there a way to fix this manually in the dungeon notepad file? Is data stored somewhere else besides the dungeon notepad file that causes this issue?
And is there any cure besides deleting the entire affected map and restart building the map from scratch?
And most importantly, is this glitch/error confined to just that specific map?
EDIT: So I deleted the entire map, in this case level 22, then created a new map on level spot 22. Saved and exit.
Then copied the entire level 22 from the dungeon notepad file from a backup into the dungeonfile with the empty level 22.
And the issue persists, so am I correct the issue lies somewhere in the dungeon notepad file itself? I'm trying to find where the corruption is essentially.
EDIT2: After testing more scenarios, I came to the simple conclusion, that you cannot stack multiple ceilings upon eachother. Who would have thought. Which is basically what I was doing. And that my map maybe isn't bugged at all. Manual object ud_ceilings on the top elevation are simply disappearing because I was placing ud_ceilings a couple of floors lower and then placing floors on top of them to make complex level design.
Maybe it's a combination of both. Who knows?

But manual object ceilings like for example ud_ceiling_a_01_01 that replace the tile layer ceiling at a lower floor is ok, until you put a 2nd us_ceiling_a_01_02 on a different elevation. Then shit starts to hit the fan, only tha last placed ceiling is displayed.
Removing all ud_ceiling objects and using other means like rotated roofs that don't replace ceiling components fixes it.
https://youtu.be/tawCXbDhkTc
a video where you can see me walking on top floors and then going under them. which would have been impossible with ceiling objects.