Hi Michael,
Could you check if this applies to your case: http://www.telerik.com/support/kb/aspnet-ajax/editor/details/radeditor-content-not-saved-after-ajax-update-in-ie9-firefox-google-chrome-and-safari?
Also, can you confirm there is no script error on the page, as this may break the editor functionality?
I an also advise that you examine the following demo that shows how a RadEditor functions properly in a RadGrid and AJAX is used: http://demos.telerik.com/aspnet-ajax/editor/examples/edittemplate/defaultcs.aspx. Could you compare it with your setup and see whether you can imitate the approach or whether you can find the difference that is causing the problem?
Yet another idea I can suggest is trying to force it to update its UI when the page renders in case this is a rendering problem. Here is a basic example:
Regards,
Marin Bratanov
Telerik
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