does “on choose menu item theObject” only work for menus like “file” or edit" or can it also be used for popup button menus?
on choose menu item theObject
if name of theObject is "source_menu" then
set theSource to title of popup button "source_menu" of window "main_window"
tell window "main_window"
set the contents of text field "message_field" to "You have selected " & theSource & " for the source drive"
update
end tell
else if name of theOject is "target_menu" then
set theTarget to tittle of popup button "target_menu" of window "main_window"
set the contents of text field "message_field" to "You have selected " & theTarget & " for the target drive"
update
end if
end choose menu item