Indeed.

Look: the map is a square, you need the right side. Somewhere near the wall, there's a mentor hidden. Regarding the tasks, I'll be exploring new ones. My editor is sometimes temperamental; it crashes or doesn't launch due to simple things. For example, when I set the goal in the first mission to cross the region (as per the manual), it didn't launch. And yes, I tried to do something different from "kill everyone," and that's how the editor reacted. Kill just one... It's as if demons have possessed it, or I don't understand something about map creation.

I understand. I was on the 3rd map, in the upper left and lower corners... that's why I missed the mentor (or rather, not because of that, but because of the quick victory "over everyone"). And it's okay... you can adjust the victory condition to Kill ‘Em All.
P.S. The third map is the most appealing and playable... maybe forget about the Campaigns; you create good landscapes, and your scenarios aren't boring. It's better to have one excellent scenario with a map than an unconvincing campaign. This third map in the campaign is quite good and could be used as a separate scenario! (with minor adjustments)