The resize handle of the Editor is not visible if only only edit mode is active (e.g. Design mode). Steps to reproduce: 1. Run an Editor with the following configuration: <telerik:RadEditor ID="RadEditor1" runat="server" EditModes="Design" ></telerik:RadEditor> Result: The whole module row is not visible, including the resize handle.
Set the RenderMode to Lightweight and the resize handler will appear.