Current questions and answers regarding the map editor.

Yesterday, I performed a similar operation on a randomly generated map in the Dungeon – the result was the same! I removed a section of the wall between areas; by the way, why can't all walls be selected and removed? The surface of the area under the removed wall is exactly the same as the adjacent area – it's level, without obstacles, and has the same pattern – but it's still impassable for the hero.
I would greatly appreciate it if you could provide more details about this impassability check and this "BLOCKED" area.
Thank you very much for your help!