Infragistics Insert dropdown in WebHtmlEditor keeps centering

Question

I added an Insert dropdown to my Infragistics WebHtmlEditor, but the items in the dropdown keep centering themselves. The first time I open the dropdown the items are left aligned, but after that they all get centered

<ighedit:ToolbarDropDown runat="server" Font-Bold="False" Font-Italic="False"
             Font-Overline="False" Font-Strikeout="False" Font-Underline="False" 
             Type="Insert" Title="Fields">
    <Items>
        <ighedit:ToolbarDropDownItem runat="server" Text="DC" Value="[Field: DC]" 
                                                    Style="text-align: left" />
        <ighedit:ToolbarDropDownItem runat="server" Text="C+DC" Value="[Field: C+DC]" 
                                                    Style="text-align: left" />
    </Items>
</ighedit:ToolbarDropDown>