The target FullRegion explorerTreeView treeView; for the callback could not be found or did not implement ICallbackEventHandler

An exception thrown by the edit tree in EPiServer edit mode when running .Net 4.0.
This described in the article EPiServer CMS 6.0 now supporting ASP.NET 4.0.
To fix this I added controlRenderingCompatibilityVersion="3.5" and clientIDMode=”AutoID” to the pages tag in web.config.

Example

Changes in web.config

<configuration>
...
  <system.web>
    <pages
        controlRenderingCompatibilityVersion="3.5"
        clientIDMode="AutoID"

Version author:
Mattias Lövström

EPiServer version

All