Current questions and answers regarding the map editor.

Is the active tile configured? This is the square that is interacted with (visiting buildings).

Yes, it is configured. After all, it is highlighted in green in the editor, so you can see where it is located.

The problem is that my hero cannot enter it, although, for example, he can leave (by hiring in the tavern). An enemy hero can easily attack or enter and capture the city. The problem is specifically with the mouse cursor in the form of a castle (it only works this way for the player who owns the city).

Added 4 minutes later
And also, you cannot enter the green square with a double click; you can only do so if you add another red, impassable square. Then you can double-click on the red square to enter the city. (But, of course, the interface panel is usually used to enter the city).