If you're still using the Isometric Grid object, you should download the Clickteam Bonus pack to get Iso Grid 2. Iso Grid 2 comes with two example files showing an isometric level editor and world viewer with a character moving about and jumping in it.
command dialog object allows you to save files. using the iso grid object 2, you can save worlds and stuff.
http://clickteam.info/extensions/ for lists of extensions
the iso grid object comes with an example of a builder - and a player