Thanks for the info about the probes. Definitely helpful. However,it is down-casting to the plugin interface properly.
The reference is actually coming from the Front Panel itself. My intention was that you call the initialize method, which calls the Front Panel method in initialize mode. The Front Panel returns it's own reference to the Initialize method, then back to the main application for SubPanel embedding. The idea was to avoid asynchronous calling by using the Run method, which calls the Front Panel as well.
I've attached the code since I might not be describing this correctly.
(side note: I had this general idea working when the Initialize method was dynamic and each child Initialize contained a static reference to the Front Panel. I wanted to avoid as many mandatory overrides as I could though.)
Thanks for the answers to far.
PluginTest.zip