Editor problem

I am helping a guy with a level so I was going to change some stuff in one of his tilesets.
But when I was done with the tileset I was going to replace it with the older version of it and something weird happened. The entire tileset dissapears and I mean for real, its all gone. The tileset was replaced by tileset33 since thats the place we had it on.

The tileset was in the levels database in worlds map. So I worked with that, tileset33 from the world map and his level. This is the second time the tileset just fully dissapears and get replaced by tileset33 from the editor tilesets.

Is it an error or what?

Is it still in the tileset folder in your level folder?

The tileset just dissapeared. But lucky for me there was an identical tileset so I took that tileset and saved it outside the worlds map and then I added it as tileset33 so I fixed the problem.

Still, replacing data with same data in the world map = data gone
I know realize it wasn't even necessary replacing the tileset since it was already in the world map.

Are you using the original editor or a modded version?

original version. try it out yourself. the file will dissapear.