This should not be coming from anywhere directly within the framework...otherwise there would be a LOT of broken dialogs our there...including ours! Here is what I would suggest. Be sure that you have the SF source built in debug mode, then do the following:
- Open your project where the issue resides.
- Open the BusinessLayer.vb file while your project is open (just click File-> Open File -> BusinessLayer.vb
- Go down to around line 1323 (this may be different for you as there has been new code added on our side so the numbering will have changed).
- Place a break point on the Set of the ParentBusinessObject property
Then run your code again. You may want to wait to add the breakpoint until you are ready to execute that one specific thing, but in any case, once you get to the Set, look at the call stack to see what is setting this to Nothing.