The mentioned errors doesn't seem to be directly related to Telerik UI controls but something general in the web app/site. You can try to reproduce the issue on a page that contains no Telerik UI controls. If the issues are still reproducible then they are not related to Telerik UI controls and possible causes must be searched somewhere else.
I can also suggest that you try the following troubleshooting steps:
- If you are not using latest Telerik UI version - 2014.3.1209, does upgrading to it helps?
- You can try to disable the AJAX, in order to ensure the problem is not AJAX related. This can be done through the EnableAJAX property of the RadAjaxManager/RadAjaxPanel.
- Since the issue is only reproducible in IE it may be related to the compatibility mode. You can try to fore the browser to edge mode
- It may be possible that some browser plug-in is causing the issue. You can try to disable all of the plug-ins and if that helps then start turning them one by one until you find the problematic one.
- Check your browser requests in order to see whether there are any failing requests.
- Try calling the radopen() method without the window object reference. Note also that radopen() method requres that you have a RadWindowManager instance on your page.
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