updating drop down options from plist record

Hello. I’m a non-developer type that has been hacking together applescripts for user automation for the past handful of years. I’m at the point that I’m looking to expand the capability of my user prompts/interactions. That is to say, I’m very new to AppleScriptObjC and Xcode. I’m getting stuck on what I assume is an easy hurdle however my Google-fu hasn’t netted me a working result thus far.

I have an Applescript App project started in Xcode. I have a plist file where I save info relating to previous times the script has been run. I’m trying to read that plist and then load the listed info as choice options in a drop down. I’ve stripped the script down to the parts below in question. It is historyList that I’m trying to update into the dropdown options but it only loads what is initially set when the property is made which is currently at “missing value”. I can successfully read the plist and return my list items in an alert dialog but not update into the drop down. I have a feeling it’s a proper connection setting in the xib that I’m missing but I’m feeling a bit lost. Can anyone point me in the right direction?

script AppDelegate
	property parent : class "NSObject"
        property historyList: missing value
	-- IBOutlets
	property theWindow : missing value
	on applicationWillFinishLaunching_(aNotification)
		-- Insert code here to initialize your application before any files are opened
        set plistFile to "/Users/myuser/Library/Preferences/opener.plist"
        set thePlist to (current application's NSDictionary's dictionaryWithContentsOfFile:plistFile) as record
        set historyList to thePlist's campaign as list
	end applicationWillFinishLaunching_
	on applicationShouldTerminate_(sender)
		-- Insert code here to do any housekeeping before your application quits
		return current application's NSTerminateNow
	end applicationShouldTerminate_
    on appSearch_(sender)
        -- do stuff when search button is pressed. sorting out drop down before continuing here
    end appSearch_
end script

Create an outlet to your menu

Use addMenuItemWithTitle:

You may also want to clear any previous menu items.