Using this wiki as an example, I made some simple modifications to make a master detail form.
The behavior is to show all the information (the master detail), and open the dialog to add a detail. To make it simple, the master only has a description field, so too as the details. The dialog is opened without any problem, but do submit, I get the error "400 Bad Request".
Making debug my code I see that the method actionAddNew receives a variable called $_, this first call (when showing the dialog).
And looking at the code generated in the form, the action attribute is set to "index.php?r=property/addNew&idgroup=3&_=somevalue".
My question is, how, when, who creates the variable $_, I guess is a variable created by YII, and not being forwarded to when submit the form gives the error.
If so, how to send that parameter is missing?