[LVL ED] Level editor problem

[Vasco]

Update:
Luckily, my map is not lost, but it acts strangely: opens well one time and crashes another time. Now I'm searching for the source of problem. The map is quite big (for me), it has a size of about 2 Mb and it includes plenty of stuff: different entities, decals, particles. But I did not use development resources like custom models or something like that what could possibly cause an error.
The map actually opens and works well in the game, so I only have problems with the level editor.