RadComboBox causes memory leak in WPF

[Rajesh]

I have used RadComboBoxes inside a Grid in my WPF application as shown below.
<tk:RadComboBox Grid.Row="3" Grid.Column="3" Style="{StaticResource DropDown}"

                       x:Name="cmbColor" Height="25" Margin="5,5,5,5" DropDownOpened="cmbColor_DropDownOpened"

                       IsEditable="False" SelectedValue="{Binding PR_COLOR}" MaxWidth="250"

                       ItemTemplate="{StaticResource DropDownCodeMeaning}"  />

I am binding the data to the combo box when the user clicked on the combo box to select an item from it.
I have used the  event "DropDownOpened" to bind data to this combo box. Below shown is the code behind.

// set the dropdown list for a combobox to all entities for a business object

       private void SetDropDown<BusObj, BusEntity>(RadComboBox cmb, ref BusObj busobj)

           where BusObj : BusinessObject<BusEntity>, new()

           where BusEntity : BusinessEntity, new()

       {

           if (busobj == null)

           {

               busobj = new BusObj();

           }

           if (cmb.ItemsSource == null)

           {

               var RecordList = busobj.GetAllEntities();

               if (RecordList.Count > 0)

                   RecordList.ApplySort("SortKey", ListSortDirection.Ascending);

               cmb.ItemsSource = RecordList;

 

           }

       }
After sets the Items Source for the combo box, the memory increases rapidly. Anyone knows why this happens?
Please help me. I am using the telerik version 2010.1.603.35.

Thanks in advance,
Rajesh V R