title: Can you link values for two JFormattedTextFields?
body: <p>I've got an interface with 2 JFormattedTextFields for which I need the values (not just the displayed text) to be identical.  Ideally they should both be editable, with a change in one being mirrored in the other.</p>
  
  <p>I started by just sharing a single Document between the two, but quickly ran into the problem that this only links the displayed text, not the underlying value.  (Silly me!)<br>
  I haven't tried adding reciprocal PropertyChangeListeners for the "value" property because I would expect that to set up an infinite loop of modification.</p>
  
  <p>Am I missing something?  Is there some way to do this?  Or am I stuck with only allowing users to edit one of the two and only having the value propagate in one direction?</p>
  
  <p>Thank you!</p>