Not only is it possible, you don't need the button if you have FileMaker 10 or 11. With those versions, you can set up a script trigger so that when you select a value in the value list, it kicks in and finds the record automatically.
If you want to find the selected manufacturer's record, you'd use a script like this:
#Run from layout referring to Manufacturer table
Enter Find Mode //clear pause check box
Set Field [Manufacturer::MfgID ; YourTable::GlobalField]
Set Error capture [on]
If you want to make this record to the current record of a list of all records, add these steps after Perform Find:
Show All Records
Sort [No dialog ; Restore]
Thanks for the help. When I set up the script as you suggested I can't select a new value from the drop down list-- actually, the drop down list won't even load long enough for me to scroll through it. Any thoughts on why this might be happening? Also, my global field is set up in the manufacturer table. Should I create a separate table for it as your script implies or is keeping it in the manufacturer table OK?
Oh I had the script trigger set up for 'On Object Enter' instead of 'On Object Exit'. Thanks, works great!!