How to add and delete features on planets

I've notice players have modified there planets. They where able to add and delete features on there planets.
I know how to add the features from CSG but how do you remove existing features and move mass spots around?

check the settings there are hotkeys to remove stuff. So to move a mex spot you remove it and add another one somewhere else.
Also when you edit planets make sure to save as lot, as it seems some people had bugs that made them lose work before.

Thank You I appreciate it!!!!!!!

Also for some unknown reason you can't delete metal deposits that are in water made by the games own random generator. I recommend you turn metal to 0 and place your own. You also have to have the correct tab selected to place what you want (like metal, starting zones). It's pretty clunky. Some of these issues may have been fixed in a latest patch so if someone wants to correct me go for it.