Current questions and answers regarding the map editor.

Is it possible to add your own "custom" textures to the editor? Yes, I mean the ones that can be applied to the ground.

Right-click on the map properties tree. In the menu that appears, select Show Hidden. Hidden map properties will appear. Find tiles, add a new element there. Click on the row in the Value column and on the ellipsis. On the left, create a new AdvMapTile object, and on the right, provide a link to the texture, etc. After saving and reloading the map, new painting textures should appear.

This way, you can even create a river of milk with shores of jelly.