RadCombobox with allowed custom text is transperant in Silk in Classic Render mode.

Video: https://www.screencast.com/t/tgubeklglq


Code to reproduce:
        <div style="width: 300px; background-color: red">
            <h2>Allow custom text</h2>
            <telerik:RadComboBox RenderMode="Classic" ID="RadComboBox1" runat="server" Width="100%" AllowCustomText="true" Skin="Silk">
                <Items>
                    <telerik:RadComboBoxItem Text="RadComboBoxItem1" />
                    <telerik:RadComboBoxItem Text="RadComboBoxItem2" />
                    <telerik:RadComboBoxItem Text="RadComboBoxItem3" />
                </Items>
            </telerik:RadComboBox>
        </div>