I think many have been playing plants vs zombies enough to get the idea what I was aiming for in this example.
it tog me forever to make it work and at the end I though ill share this made example to give everyone an idea how to make basic inventory where you put items into inventory by clicking on them and when you click on items in the inventory, they are moved back to their place. Also to avoid gaps, the items in the inventory reorganize themselves.
Sorry if the descriptions in this file are too confusing...
File: dl.dropboxusercontent.com/u/5214903/GM/inventory.capx