I have an UltraChart inside an update panel. The initial load of the page renders the chart correctly, but if I do any sort of postback, the old image remains. Here are the things I've checked: 

• The data source DOES refresh on the postback -- I've analyzed the data after the postback and it does indeed contain the new data (which is ultimately why I'm posting this message).
• A new image DOES NOT get created in the file system, so it seems stuck on the old image or just plain doesn't re-render the chart

Here is the code which is creating this:

protected void Page_Load(object sender, EventArgs e)
{
    ChartDataBind();
}

private void ChartDataBind()
{

// Added this per the suggestion on another forum post to resolve a similar issue
UltraChart1.DataSource = null;
UltraChart1.Series.Clear();

SqlConnection conn = new SqlConnection(WebConfigurationManager.ConnectionStrings["BillingProductivityConnectionString"].ConnectionString);
SqlCommand cmd = new SqlCommand("uspEmployeeProductivityDetails_TransactionTrend", conn);
cmd.CommandType = CommandType.StoredProcedure;

cmd.Parameters.AddWithValue("@ClientID", hdnClientID.Value);
cmd.Parameters.AddWithValue("@ClientEmployeeID", hdnEmployeeID.Value);
cmd.Parameters.AddWithValue("@FromDate", lblFromDate.Text);
cmd.Parameters.AddWithValue("@ToDate", lblToDate.Text);
cmd.Parameters.AddWithValue("@TransFilter", WebDropDown1.CurrentValue ?? "");
cmd.Parameters.AddWithValue("@QtyOrPts", rblTT_QtyOrPts.SelectedValue);

DataTable dt = new DataTable();
conn.Open();
dt.Load(cmd.ExecuteReader());
conn.Close();

cmd.Dispose();
conn.Dispose();

UltraChart1.DataSource = dt;
UltraChart1.DataBind();

}

<asp:UpdatePanel ID="upnlChart" runat="server">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="rblTT_QtyOrPts" />
<asp:AsyncPostBackTrigger ControlID="WebDropDown1" EventName="SelectionChanged" />
</Triggers>
<ContentTemplate>

<div class="content-panel-header">
<div style="display: inline-block;">Transaction Trend</div>
<div class="content-panel-header-criteria">

<div style="display: inline-block; ">Metric: </div>
<asp:RadioButtonList ID="rblTT_QtyOrPts" runat="server" AutoPostBack="true" RepeatDirection="Horizontal" RepeatLayout="Flow" style="display: inline-block; margin-right: 25px;">
<asp:ListItem Text="Qty" Value="Qty" Selected="True" />
<asp:ListItem Text="Points" Value="Pts" Selected="False" />
</asp:RadioButtonList>
<asp:RadioButtonList ID="rblTimePeriod" runat="server" AutoPostBack="true" RepeatDirection="Horizontal" RepeatLayout="Flow" style="display: inline-block; margin-right: 25px;">
<asp:ListItem Text="Hours" Value="Hours" Selected="True" />
<asp:ListItem Text="Days" Value="Days" Selected="False" />
<asp:ListItem Text="Months" Value="Months" Selected="False" />
</asp:RadioButtonList>
<div style="display: inline-block;">
<asp:UpdateProgress ID="UpdateProgress1" runat="server">
<ProgressTemplate>
<asp:Image ID="img2Ajax" runat="server" ImageUrl="~/Images/ajax-loader.gif" style="height: 15px; display: inline-block;" />
</ProgressTemplate>
</asp:UpdateProgress>
</div>
</div>
</div>

<div class="criteria-panel">Transaction Filter
<ig:WebDropDown ID="WebDropDown1" runat="server" Width="800px" DataKeyFields="Trans" DataSourceID="ObjectDataSource2" TextField="Trans" ValueField="Trans" OnSelectionChanged="WebDropDown1_SelectionChanged" AutoPostBackFlags-SelectionChanged="On">
</ig:WebDropDown>
</div>

<asp:ObjectDataSource ID="ObjectDataSource2" runat="server" OldValuesParameterFormatString="original_{0}" SelectMethod="GetData" TypeName="Dashboards.BillingProductivityDataSetTableAdapters.uspProductivity_GetEmployeeTransactionTypesTableAdapter">
<SelectParameters>
<asp:ControlParameter ControlID="hdnClientID" Name="ClientID" PropertyName="Value" Type="Int32" />
<asp:ControlParameter ControlID="hdnEmployeeID" Name="ClientEmployeeID" PropertyName="Value" Type="Int32" />
<asp:ControlParameter ControlID="lblFromDate" Name="FromDate" PropertyName="Text" Type="DateTime" />
<asp:ControlParameter ControlID="lblToDate" Name="ToDate" PropertyName="Text" Type="DateTime" />
</SelectParameters>
</asp:ObjectDataSource>

<igchart:UltraChart ID="UltraChart1" runat="server" ChartType="LineChart" EmptyChartText="Data Not Available. Please call UltraChart.Data.DataBind() after setting valid Data.DataSource" Height="487px" Version="16.1" Width="1036px" DeploymentScenario-Scenario="FileSystem">
</igchart:UltraChart>

</ContentTemplate>
</asp:UpdatePanel>