I had seen this page earlier,
but it did not answer my main question. That was: "how can I get the
calendar to update the date  more than once in a session?" I have
managed to make the calendar  update the date text  box whenever either
the month  or year  are changed, but if I try to do that a second time
without first closing the form  and then re-opening it, all I get is a
blank text box.
If I revert to using days as well, and clicking on the day  buttons,
then it works as it should; however, I only wish to select month and
year, and then have the date entered.