Choose a Waiting context in OmniFocus

gistfile1.scpt

-- accumulate all context names that contain the "wait" substring
repeat with anItem in (complete "wait" as context)
    set waitingForContextNamesList to waitingForContextNamesList & {(name of anItem)}
end repeat
		
choose from list waitingForContextNamesList with prompt "Choose Waiting context…" OK button name "Set" cancel button name "Cancel"
set chosenWaitingForContext to result as string
set theContextID to id of item 1 of (complete chosenWaitingForContext as context)
-- this last line fails even if theContextID is correct
set theWaitingForContext to first context whose id is theContextID