RadEditor Dialogs don't work in Medium Trust and U have the below in your PageStateAdapter.browser file.
How can I force a single page to NOT use the PageStateAdapter.browser or ignore Radcompression for a given page?
How can I force a single page to NOT use the PageStateAdapter.browser or ignore Radcompression for a given page?
PageStateAdapter.browser
<browsers> <browser refID="Default"> <controlAdapters> <adapter controlType="System.Web.UI.Page" adapterType="Telerik.Web.UI.RadSessionPageStateCompression" /> </controlAdapters> </browser> </browsers>