I have a linked collection to show n the xamdatagrid. 

here is my grid code. 

   <infragistic:XamDataGrid.FieldLayoutSettings>
                                                <infragistic:FieldLayoutSettings AutoGenerateFields="False" 
                                            AutoFitMode="Always" 
                                            AddNewRecordLocation="OnTopFixed"
                                            AllowAddNew="False"
                                            SupportDataErrorInfo="RecordsAndCells"
                                            DataErrorDisplayMode="Highlight"
                                            AllowDelete="True" SelectionTypeRecord="Single"/>
                                            </infragistic:XamDataGrid.FieldLayoutSettings>
                                            <infragistic:XamDataGrid.FieldLayouts>
                                                <infragistic:FieldLayout>
                                                    <infragistic:FieldLayout.Fields>
                                                        <infragistic:TemplateField Name="TopHorizon" Label="Top horizon">
                                                            <infragistic:TemplateField.DisplayTemplate>
                                                                <DataTemplate>
                                                                    <controls:PresentationBox   Name="TopHorizon" DomainObject="{igEdit:TemplateEditorValueBinding UpdateSourceTrigger=PropertyChanged, NotifyOnValidationError=True}"
                                                                                                Validation.ErrorTemplate="{StaticResource CommonErrorTemplate}"  ></controls:PresentationBox>
                                                                </DataTemplate>
                                                            </infragistic:TemplateField.DisplayTemplate>
                                                        </infragistic:TemplateField>
                                                        <infragistic:TemplateField Name="BottomHorizon" Label="Bottom horizon">
                                                            <infragistic:TemplateField.DisplayTemplate>
                                                                <DataTemplate>
                                                                    <controls:PresentationBox   Name="BottomHorizon" DomainObject="{igEdit:TemplateEditorValueBinding UpdateSourceTrigger=PropertyChanged, NotifyOnValidationError=True}"
                                                                                                Validation.ErrorTemplate="{StaticResource CommonErrorTemplate}"  ></controls:PresentationBox>
                                                                </DataTemplate>
                                                            </infragistic:TemplateField.DisplayTemplate>
                                                        </infragistic:TemplateField>
                                                         </infragistic:FieldLayout.Fields>
                                                </infragistic:FieldLayout>
                                            </infragistic:XamDataGrid.FieldLayouts>
                                        </infragistic:XamDataGrid>

And my bottomhorizon changes when new layer is added. But since the bottom horizon is binded without setter

       public dynamic BottomHorizon
        {
            get { return _model.BottomHorizon != HorizonFactory.NullObject ? _model.BottomHorizon : null; }
        }ll; }

The correspoding UI is not refreshes even dough I call  OnPropertyChanged("");

I tried to refresh the whole list to force the update (CollectionViewSource.GetDefaultView(this.LayerList).Refresh();) still not working. 

How can I fix this issue? Do I need different binding?