Multiple controls with the same ID were found. FindControl requires that controls have unique IDs

[RichJ]

Hi all,

I'm hoping someone out there may be able to help with this issue I'm having.

Scenario:
I have a page containing a radsplitter which is divided into 3 main panes: Across the top, down the left-hand side and the third is the main content panel.

Within the left-hand pane I have nested splitters and a panelbar, using templated panels that contain ajaxified radgrids (using advanced binding).  In the main content pane I have a tabstrip and multipage.

No controls are being added dynamically/programmatically, other than tabs being added using client-side scripts from within the main content pane.

Now the problem:
If I do not open any tabs everything works great - the grids page nicely and everyone is happy.
If, however, I open a tab, after 3-4 paging operations on the grids I get the dreaded Multiple controls with the same ID were found. FindControl requires that controls have unique IDs.

Now I *know* there are no controls being added between the ajax paging postbacks.  And the error only occurs after 3-4 actions taking place on the grid as opposed to immediately.  Disabling ajax I still continue to get the error.
I have no RadAjaxPanels anywhere - everything is hooked up using the RadAjaxManager.
If I remove the grid outside of all the radsplitter/panelbar elements the problem persists.
I have gone through all my code and made absolutely certain that every control has a unique ID (radcodeblocks, pageviews etc).
There are no pageLoad() or document.ready functions being used.

I'm completely stumped.  the stack trace shows that the problem occurs after the tabstrip PreRender process:

[HttpException (0x80004005): Multiple controls with the same ID 'ctl01' were found. FindControl requires that controls have unique IDs.]
   System.Web.UI.Control.FillNamedControlsTable(Control namingContainer, ControlCollection controls) [phone]
   System.Web.UI.Control.FillNamedControlsTable(Control namingContainer, ControlCollection controls) +317
   System.Web.UI.Control.FillNamedControlsTable(Control namingContainer, ControlCollection controls) +317
   System.Web.UI.Control.FillNamedControlsTable(Control namingContainer, ControlCollection controls) +317
   System.Web.UI.Control.FillNamedControlsTable(Control namingContainer, ControlCollection controls) +317
   System.Web.UI.Control.FillNamedControlsTable(Control namingContainer, ControlCollection controls) +317
   System.Web.UI.Control.FillNamedControlsTable(Control namingContainer, ControlCollection controls) +317
   System.Web.UI.Control.FindControl(String id, Int32 pathOffset) +320
   Telerik.Web.UI.RadTabStrip.OnPreRender(EventArgs e) +103

I've reviewed this post http://www.telerik.com/help/aspnet-ajax/ajax-content-type.html but it's not applicable because I'm not dyanmically adding controls.  I've also tried the javscript from this post http://www.telerik.com/help/aspnet-ajax/tabstrip-faq.html but still the problem persists.

Can anyone offer any suggestions about where I should should look next?

Help!

Rich

[RichJ]

Forgot to mention: I'm using the latest build of the controls 2013.2.717.40
and I'm not calling any explicit FindControl functions.

[Angel Petrov]

Hello Rich,

Since the problem is reproducible outside the RadSplitter environment maybe it lies somewhere in the grid configuration. However in order to provide a precise answer I would like to ask you to show us the markup and code-behind of the grid. Without having a better understanding of the implementation it would be hard to determine the root cause of the issue.

Regards,
Angel Petrov
Telerik