Can you be more specific? If you are clicking the toolbar button, it's not supposed to do anything except choose which action to drop in the area below when you click down there. After that, you can double-click on the dropped action to set its properties.
If all you want to do is get a DDL script for an object, the easiest way to do that is to go to the Schema Browser, find the object you want, and then click on the Script tab on that right.
