[quote user="Maury"]Bentley.MicroStation.WinForms.Adapter[/quote]
Thanks, Jan and Maury, for reminding me about that! Like so much in the .NET API, it's not documented.
[quote user="Maury"]...in combination with AttachAsTopLevelForm(addin, true)[/quote]
Without that the WinForm appears but is frozen. With that statement it behaves as expected.
[quote user="Maury"]I created a custom control that will toggle back to the regular form when in design mode[/quote]
Cool!
[quote user="Jan Slegr"]I have not tested WinForms in CONNECT Edition yet[/quote]
The only example of Winforms.Adapter that I can find in the Update 3 SDK is WPFDemo3.cs. No other example uses that adapter.