When you edit the properties of a table in the content editor of most page types, extra cells are added. Check the following animation to see the issue:
This issue has been reproduced in empty (clean) instances of Sitecore 8.1 rev 160302, 160519 and Sitecore 8.2 rev 161221, and has been registered by Sitecore as a bug at their Bug Tracking System with the reference number 101901.
To resolve the issue, please update the Telerik RTE assemblies to the newer version:
- Extract the Telerik.Web.UI.dll and Telerik.Web.UI.Skins.dll assemblies into your bin folder (replacing the existing ones);
- Replace the Telerik.Web.UI.XML file in your bin folder with the attached one;
- Add the Telerik.Web.UI assembly binding to your web.config:
<runtime> <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1"> ... <dependentAssembly> <assemblyIdentity name="Telerik.Web.UI" publicKeyToken="121fae78165ba3d4" /> <bindingRedirect oldVersion="2015.1.401.45" newVersion="2015.3.930.45" /> </dependentAssembly> </assemblyBinding> </runtime>