The inventory list is 100K items of the class inventory which is defined by:

string description

string description2

string qadcode

string per

This seems to be related the issue I mentioned in the previous post. I assume the items in the InventoryList (i.e. what will be the items of the itemsprovider) is just a standard CLR class. What datatype is QADCode on that object? I just want to make sure my test is accurately replicating this scenario.

Absolutely -- I declare my ObjectDataProvider in the code behind (just as an experiment, but I get the same result even in XAML).  App.InventoryList is a static list...

            ObjectDataProvider dp = new ObjectDataProvider();
            dp.IsAsynchronous = true;
            dp.ObjectInstance = App.InventoryList;

I then add it to the page resources.

            this.Resources.Add("InventoryDP", dp);

In Xaml I create a comboitemsprovider for it:

        <igEditors:ComboBoxItemsProvider x:Key="QADCodes" DisplayMemberPath="QADCode"
           ValuePath="QADCode" ItemsSource="{Binding Source={StaticResource InventoryDP}}">                   
        </igEditors:ComboBoxItemsProvider>

Then, in a grid I reference the provider:

                                                        <igDataGrid:Field Name="QADCode" Label="CC No./Part No.">
                                                            <igDataGrid:Field.Settings>
                                                                <igDataGrid:FieldSettings LabelMinWidth="100" EditorType="{x:Type igEditors:XamComboEditor}" >
                                                                    <igDataGrid:FieldSettings.EditorStyle>
                                                                        <Style TargetType="{x:Type igEditors:XamComboEditor}" >
                                                                            <Setter Property="ItemsProvider" Value="{StaticResource QADCodes}" />
                                                                            <Setter Property="IsEditable" Value="true" />                                                                           
                                                                            <EventSetter Event="KeyUp" Handler="grdUsedPartValue_KeyUp" />
                                                                            <EventSetter Event="SelectedItemChanged" Handler="Inventory_SelectedItemChanged"/>
                                                                        </Style>
                                                                    </igDataGrid:FieldSettings.EditorStyle>
                                                                </igDataGrid:FieldSettings>
                                                            </igDataGrid:Field.Settings>
                                                        </igDataGrid:Field>

Let me know if you see any way to improve this...