Below is part of the XAML for my grid with RadComboBox. I noticed that if the itemsource for the combo is assigned once and if it gets changed again, and the drop down is opened again, the new itemsource doesn't take effect. It still has the old items. The DropDownOpenEvent has the old list of items. The binded property to itemsource is an Observable collection.
Thanks
Shipra
<Grid>
<telerikGrid:RadGridView x:Name="RequirementJurisdictionOverrideGridView" Grid.Column="0" IsReadOnly="False" ColumnsWidthMode="Fill" AutoGenerateColumns="False"
ItemsSource="{Binding Path=RequirementJurisdictionOverrideList}"
ShowGroupPanel="False" IsEnabled="{Binding IsEditable}" IsEnabledChanged="RequirementJurisdictionOverrideGridView_IsEnabledChanged" >
<telerikGrid:RadGridView.Columns>
<telerikGrid:GridViewDataColumn Width="20">
<telerikGrid:GridViewDataColumn.CellStyle>
<Style TargetType="GridView:GridViewCell">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="GridView:GridViewCell">
<Button Content="X" Click="RemoveRequirementJurisdictionOverride_Click" Width="20"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</telerikGrid:GridViewDataColumn.CellStyle>
</telerikGrid:GridViewDataColumn>
<telerikGrid:GridViewDataColumn HeaderText="Jurisdictions">
<telerikGrid:GridViewDataColumn.CellStyle>
<Style TargetType="GridView:GridViewCell">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="GridView:GridViewCell">
<Controls:RadComboBox ItemsSource="{Binding AllJurisdictions}" DisplayMemberPath="JurisdictionName" SelectedItem="{Binding Path=RequirementJurisdictionOverrideJurisdiction, Mode=TwoWay}"></Controls:RadComboBox>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</telerikGrid:GridViewDataColumn.CellStyle>
</telerikGrid:GridViewDataColumn>
<telerikGrid:GridViewDataColumn HeaderText="Functions">
<telerikGrid:GridViewDataColumn.CellStyle>
<Style TargetType="GridView:GridViewCell">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="GridView:GridViewCell">
<Controls:RadComboBox ItemsSource="{Binding OverrideFunctions}" DisplayMemberPath="FunctionName" SelectedItem="{Binding Path=RequirementJurisdictionOverrideFunction, Mode=TwoWay}"></Controls:RadComboBox>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</telerikGrid:GridViewDataColumn.CellStyle>
</telerikGrid:GridViewDataColumn>