Got another one...

If you subclass a bizobj class inside another class, like this perhaps:

public partial class MyForm : mmBusinessForm
{
  // ....
  protected class BOSubclass : BO
  {
   //...
  }
  //...
}

and then attempt to bind a UI control to that bizobj

 // ... (MyForm.Designer.cs)
 this.cboComboBox.BindingSource = "BOSubclass";
 // ...

Then mmBusinessBaseForm.GetBizObj(..) calls mmReferenceCollection.Get(string) which goes wrong at the following point (mmCollections.cs line 54):

  ObjectType = ObjectType.Substring(ObjectType.LastIndexOf(".")+1);

This is because at this point ObjectType is something like "name.space.MyForm+BOSubclass"

I leave it to you what to do about this - including documenting it quietly and leaving as is. It is however annoyingly difficult to debug.

There's an easy workaround - Don't do that! (moving the subclass out into the namespace means it's no longer a nested class and has dots just like a bought one.