Ok, apparently this is more complicated than I thought. So here's the update:
On the page for which I posted the code above, we have added code-behind to automatically save the dock layout each time the dock is moved. Here is that code:
On this page is where we see the behavior of not being able to collapse a dock until after we have dragged it (and presumably the savedocklayout has fired).
However, on the other page I mentioned, there is NO code to save the dock layout, because in fact there is just one dock at this time. On that page, the dock will not collapse no matter what we do (in IE; once again, works fine in Firefox). I drag it around, and it still won't collapse.
Here is the code for that dock:
Any help on this is greatly appreciated.
Thanks,
Gene