FilterDescriptors doesn´t update correctly

[Gerardo]

Hello, I´m working with 2011.3.1116.40 WPF version, I handle Filtered event, when I follow these steps, FilterDescriptors doesn´t update correctly:

1- Check one filter item -> FilterDescriptors OK.
2- Uncheck "Select all" -> FilterDescriptors wrong. FilterDescriptos continues with the last value.

It happens on filtered method.

Thanks for your support.