How to change color of read only dropdownlist on ie9

Question

Hello

I am trying to change the fore color of read only dropdownlist.

its work fine with firefox and chrome, but not in internet explorer 9
someone know how to solve the problem ?

this is my code:

  <asp:DropDownList ID="ProblemTypeIDdrp" runat="server"
  DataSourceID="EntityDataSource1" DataTextField="ProblemName"
  DataValueField="ProblemTypeID" SelectedValue='<%# Bind("ProblemTypeID") %>'
  Enabled="False" Font-Bold="True"  ForeColor="#6666FF">
  </asp:DropDownList>

thank you