You don't have the right PostBackOptions.... Try this instead:

<PostBackOptions 

EnableReloadingUnselectedTab="true" 

EnableAjax="true" EnableLoadOnDemand="false" />

  <asp:ScriptManager ID="ScriptManager1" runat="server">
  </asp:ScriptManager>
  <asp:UpdatePanel ID="UpdatePanel1" runat="server">
   <ContentTemplate>
    <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
    <ig:WebTab ID="WebTab1" runat="server" Height="184px" Width="700px" StyleSetName="Default"
     EnableOverlappingTabs="true">
     <Tabs>
      <ig:ContentTabItem runat="server" Text="tab 1">
      </ig:ContentTabItem>
      <ig:ContentTabItem runat="server" Text="tab 2">
      </ig:ContentTabItem>
      <ig:ContentTabItem runat="server" Text="tab 3">
      </ig:ContentTabItem>
     </Tabs>
     <PostBackOptions EnableAjax="true" EnableLoadOnDemand="true" />
    </ig:WebTab>
   </ContentTemplate>
  </asp:UpdatePanel>

 Protected Sub WebTab1_SelectedIndexChanged(ByVal sender As Object, ByVal e As Infragistics.Web.UI.LayoutControls.TabSelectedIndexChangedEventArgs) Handles WebTab1.SelectedIndexChanged
  Label1.Text = Now.ToLongTimeString
 End Sub

The SelectedIndexChanged event only first for the first click on each tab, have tried a number of combinations with PostBackOptions with no luck.

Can you show us a snippet of your code so we can help you better?

Already have the webtab control in an update panel.  Trying to get it to fire on every tab change, not just the first click.

Actually, I have found out a simpler workaround... Just add a UpdatePanel around the WebTab control... Once you do that then the event will be fired for the first tab click.

Cheers,

Wagner Danda da Silva