RadComboBox

[Sam]

I have a RadComboBox. It works fine (you can see attach file rcb_ok.jpg)

However, there is a problem occurs when I change RadCombobox size smaller.
I select an item. The text of selected item does not display on the input area of RadComboBox but I still get the selected value of it??? (see attach file rcb_problem1_selectitem.jpg & rcb_problem1_displayempty.jpg)
After that, I click on RadComboBox again, the text of selected item is displayed??? (see attach file rcb_problem2_displayselecteditem.jpg)

Would be grateful for any ideas to solve the problem?

Thank you!

Sorry about my thread name unclear :(

Here is my code:
<telerik:RadComboBox    ID="rcbSchool" runat="server" Width="100px" Skin="Web20"/>

Code behind:
private void LoadSchool()
{
        DataTable data = new DataTable();
        string text = string.Empty;
        SqlDataAdapter adapter = new SqlDataAdapter("SELECT * FROM tblSchool",
                   ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString);

        adapter.SelectCommand.Parameters.AddWithValue("@text", text);
        adapter.Fill(data);

        this.rcbSchool.DataSource = data;
        this.rcbSchool.DataTextField = "Name";
        this.rcbSchool.DataValueField = "ID";
        this.rcbSchool.DataBind();
    }

[Sam]

Please give me any solutions to solve this problem......:(
Thank you!