With RadEditor for AJAX Version 2013 Q3 it is not possible to edit tables in Design view.  

Clicking within a table seems to cause the editor to lose keyboard focus, the cursor is not visible.

The problem is reproducible on the Telerik WYSIWIG Editor demo page.

When an image in the list view of the image manager is dropped outside the dialog, a duplicate of this image is stuck to the cursor. After selecting another image, the ghost image remains and overlays the upload window.

In the Radeditor.  Create a table with multiple rows, multiple columns optional.  Add text in the first row.  Add a bulleted list in the second row.  Save the html and the bulleted list is rendered above the table.  It looks like when you type in text and then convert it to a bulleted list it removed the <td> tag and replaces it with <ul><li></li></ul> which means it won't render in the table properly.  I tested this with the demo radeditor as well and can duplicate every time.

radeditor adding <p>&nbsp;</p> . Actual HTML just have <p></p>

Also when we swtich beween edit, HTMl and preview . It add &NBSP;

Content appears double if there is a Style element inside it and the Spell Check is triggered.

After upgrading to Q2 2003.2.611, I receive this error when an editor is being rendered, whether in a grid as a columntype, or standalone editor. If I remove the column, my popup comes up fine. I've even tried using the latest internal build to no avail.

Error: Unhandled exception at line 3407, column 1 in http://localhost:46674/Telerik.Web.UI.WebResource.axd?_TSM_HiddenField_=ctl00_rsmMaster_TSM&compress=1&_TSM_CombinedScripts_=;;Telerik.Web.UI,+Version=2013.2.709.45,+Culture=neutral,+PublicKeyToken=121fae78165ba3d4:en-US:69657036-201e-4b8d-ba50-faac1961b436:1569bb5f:63b115ed:874f8ea2:dc7e0bd:30f1f089:92fe8ea0:fa31b949:19620875:490a9d4e

0x800a01b6 - JavaScript runtime error: Object doesn't support property or method 'registerControlProperties'

Radeditor when initially set as visible="false", the toolbar border images never renders when the control is later set to Visible="true".

The desired behavior cannot be achieved out of the box with the content provider from this KB article, because the paths to the images are passed to a generic handler.
The main reason it can't be achieved at the moment is that the latest moment of the page life-cycle of the FileBrowser.ascx dialog, when the user can set the FileExplorer's InitialPath is before the Page_Load event, but the path to the preselected in the Editor item is passed in the Page_Load event and the initial path is reset internally.

Whe you're trying to add an image with "#" or "&" symbols in it's title - image displays as corrupted in image editor.