did you use a different name for the widget and the underlying template?
If so, this will fail. I think this can fairly be described as a bug, or at least
unexpected behaviour. Also the lack of an error message compounds this.
However, we are completely re-factoring the widget workflow, to make it simpler,
so bear with us. This will not affect any code you write for your widgets,
you may just have to fill the forms in again.