How are you trying to get the value? Would it have any impact on the program
logic that Load event on the containing Page fires before Load on controls
it contains?

I've taken a quick look at the control and may look more deeply later. It
looks pretty nice, and we might need such a thing, so your offer is
tempting. My one negative comment so far is that your "unregistered" message
box displays too often. It gets in the way of testing the control. I would
think that once per activation, or once per hour would be enough.

For the moment, I'll say that I recently had trouble with a complex control,
when I made assumptions about the order in which events fired. I got out of
this mess by instrumenting the hell out of the code, adding Page.Trace.Write
statements to every possible overload of a Control method and then having
the method call its base class version. After simplifying the problem to its
smallest possible broken version and poring over the event traces, I finally
tracked down my problem. Maybe the same technique will work for you.

Note that Page.Trace cannot be referenced in design mode, so you'll want to
create your own "PageTraceWrite" method which checks for design mode before
even referencing "Page.Trace", much less calling Page.Trace.Write.