It is now possible to delete stuff in your mapeditor! It took me a good two hours to code out the functionality and then debug and fix it. Along the way, I made an improvement to the map engine's camera. You can save it and then reload it to see if it work.
I also learned that integers are immutable. Bumber!
Then the rest of my time are spent on figuring a way to display these characters and items graphics on the object chooser so I can get started on adding support for modifying the map. They don't work quite the same way as the map engine do. By the end of my 4 hours effort, I think I was quite close to finishing the mechanism for drawing these images.