ValidationSummary doesn't show combobox validation error

Question

In silverlight 4, I have combobox and other controls. ValidationSummary can and does shows control's validation errors, except comboboxes errors. Here is my XAML

<ComboBox x:Name="cmbGender" Grid.Row="6" Grid.Column="1" Margin="5,5,0,0" Width="100"
                                      HorizontalAlignment="Left" VerticalAlignment="Center" 
                                      sdk:ValidationSummary.ShowErrorsInSummary="True"
                                      ItemTemplate="{StaticResource cmbGenderItemTemplate}"
                                      IsEnabled="{Binding IsAddingOrEditing}" 
                                      ItemsSource="{Binding Genders}" 
                                      SelectedItem="{Binding EmployeeDetails.Gender, Mode=TwoWay, 
                                        ValidatesOnDataErrors=True, ValidatesOnNotifyDataErrors=True, 
                                        ValidatesOnExceptions=True, NotifyOnValidationError=True}" 
                                    />

And in my VM I have this Metadata bind to SelectedItem

    [Display(Name = "LabelGender", ResourceType = typeof(AnnotationResources))]
    [Required(ErrorMessageResourceName = "ValidationGenderRequired", ErrorMessageResourceType = typeof(AnnotationResources))]
    public GenderData Gender
    {
        get
        {
            return _gender;
        }
        set
        {
            if (value != _gender)
            {
                _gender = value;
                this.RaisePropertyChanged("Gender");

                Validator.ValidateProperty(_gender, new ValidationContext(this, null, null) { MemberName = "Gender" });
            }
        }
    }

And this is my XAML for validationSummary

<sdk:ValidationSummary Margin="0,5,0,0" Target="{Binding ElementName=gridDetails}" />

But if I call Validator.TryValidateObject, those errors (comboBoxes errors) are there.
Please help, already spent days googling for this issue with no luck.

Answer 1

Actually the problem was in this property setter line:

if (value != _gender)

Douh!!