First, thank you for the plugin... this is much needed functionality. Unfortunately I am not able to get it working. I have added the behavior and the partial to my list view. I have the 'duplicate' column in the list view but when I click it I am taken to a page with no form. I added a debugbar line to dump the model and context in your duplicate function:
$model = $this->controller->formExtendModel($model) ?: $model;
+++Debugbar::info(array('model' => $model, 'context' => $this->context));
The model seems to be properly populated and context is set to 'duplicate' , but the form is not rendering. Do you have any ideas of where I can dig further?
I'm very sorry for the late answer.
The documentation was lacking some information.
You have to create a view called duplicate, like create or update.
Please take another look to the Documentation it has been updated.