openField select text not working

[Sivakatirswami]

I have a small field for entering a query string. I want the text to  
be selected automatically when the user clicks in there...

on openField
    select text of the target
end openField


should work, according to docs. I have a very visible highlight color  
set, easily seen if you double click the word. But simply clicking  
the field does nothing..

A test:

on openField
    put text of the target
end openField

Show the msg is being sent, as the text of the query field appears   
in the msg box. Any clues on why it won't select?

on a side issue:  is this the optimum way to implement Cmd-A for  
select all text in a fld? It works...

in stack script

on commandKeyDown theKey
   if theKey is "a" then select text of the target
end commandKeyDown