Tom,
Microsoft's approach as I understand it has always been to provide a rich
customization capability but ship with only the most popular or desired
features. This opens up a huge third-party market for customized and
enhanced products. If I were a product manager trying to decide what to
implement, I don't think that an opening delay would have been very high on
the list. I only found a handful of references to the capability when I
searched for it. For someone like me who doesn't get to code all day every
day, third-party components that do exactly what I want are well worth the
relatively small cost involved. If you are working on a tight budget, then
perhaps that isn't the way to go.
You might be able to write a custom event handler to do what you want.
Perhaps one of the forum gurus will jump in here and suggest a way to do
that. Unfortunately, I don't know enough about it to guide you through it.
If the cost of third-party products is an issue, you can always try the
first option that I mentioned and write a CSS-based menu with javascript.
This is how I usually end up doing most of my menus anyway, even on ASP.NET
pages. I find this a lot easier than writing a long string of attributes or
using the properties box in Visual Studio.
HTH
Steve