Drag and Drop disables my run -- help?

I have a table view that lists out the files that are dragged onto it. The action runs fine before I drag any files onto it, after however it disables the run. What’s going on?

on add_item_to_list(theItemName, theDataSource)
	set the theItem to get (POSIX file (theItemName as string)) as alias
	set is_a_file to true
	if is_a_file is true then
		set theDataRow to make new data row at end of data rows of theDataSource
		set contents of data cell "fileNameColumn" of theDataRow to extract_filename_from(theItem) as string
		set contents of data cell "filePathColumn" of theDataRow to theItem
		set contents of data cell "headerOption" of theDataRow to yes
		set contents of data cell "annotateOption" of theDataRow to yes
	end if
	
end add_item_to_list

on drop theObject drag info dragInfo
	set theFiles to {}
	set preferred type of pasteboard of dragInfo to "file names"
	try
		set theFiles to the contents of pasteboard of dragInfo
	on error
		display dialog "Could not set the list of files for some reason."
	end try
	
	if (count of theFiles) > 0 then
		set theDataSource to data source of theObject
		set update views of theDataSource to false
		
		repeat with theItem in theFiles
			add_item_to_list(theItem, theDataSource)
		end repeat
		
		set update views of theDataSource to true
	end if
	set preferred type of pasteboard of dragInfo to ""
	
	return true
end drop

I don’t know much about Automator (read zilch), but an AppleScript droplet application contains an ‘on open’ handler. Search a bit in the AppleScript | OS X section of the forum.

I’m thinking it’s relating to item focus. When I save it as an app and “show that item when run”, the problem doesn’t happen. It’s something relating to the workflow. My action is meant to run as a stand alone action so this doesn’t pose a problem to me. Thanks for the thought.