Solaris Motif native peers for AWT objects utilise the XmNuserData
resource for storing a reference back to the Java "target" object.

In the case of AWT TextField, has always(?) used this field for a second,
simultaneous and conflicting purpose.
When in "password" mode (ie an echo character is defined) a pointer to
real text field contents is stored as the XmNuserData.

In the course of fixing 4084454, at the creation of the XmTextField widget,
the intialisation of this peer was changed to initialise the value of
XmNuserData to NULL, to reflect the already established usage of this
resource for storing the password.

It is now apparent that Drag and Drop, at least, depends on the XmNuserData
in the widget referring back to the Java object.

Since this is the general mechanism, we need to find a different location
to store the specific data needed by the TextField in password mode.