Hi,

which browser do you use? In IE9 and the newest version of Google Chrome it should definitely work. Did you also specify your textbox in the following way (if it is an ASP.NET control)?

<asp:TextBox ID="Textbox1" runat="server" CssClass="textbox1" />

After that you should modify your CSS in the following way:

.textbox1
{
    border-radius: 6px;
    ...
}