Hah! I got it to work ---- well, sort of...... At least enough to feel like I finally accomplished something. So thanks!
However, I can only get the selections to work if I hard code the global value; meaning, if I enter in the number of the id into a text box set to the global value field.
How do I get the id of whatever dropdown box I'm using to be = to the global ID? I can't set up a relationship because Inventory is the master. I can do the reverse (material_id = global_desc) but that doesn't get me very far.
Isn't there someway just to write a script that says, "When dropdown box y selects value x then global_desc becomes x?"