The spellchecker does not recognize words with non-breaking spaces between them as separate.
A workaround when pasting text into the RadRichTextBox is to subscribe to the CommandExecuting event of the control, get the paste text from the clipboard and replace all non-brekaing spaces with spaces.

private void editor_CommandExecuting(object sender, Telerik.Windows.Documents.RichTextBoxCommands.CommandExecutingEventArgs e)
        {
            if (e.Command is PasteCommand)
            {
                var pasteText = Clipboard.GetDataObject().GetData("HTML Format") as string;
                if (pasteText != null)
                {
                    pasteText=  pasteText.Replace("&nbsp", " ").Replace(' ',' ');
                    var originalDataObject = Clipboard.GetDataObject();
                    DataObject dataObject = new DataObject();
                    foreach (string format in originalDataObject.GetFormats())
                    {
                        dataObject.SetData(format, originalDataObject.GetData(format));
                    }
                    dataObject.SetData("HTML Format", pasteText);
                    Clipboard.SetDataObject(dataObject);
                }               
            }
        }

When a continuous section break is inserted on a page containing an image and with a watermark applied, the watermark is shown on top of the other document elements. The issue is observed only on the page with the section break.

A NullReference exception is thrown when the content of a MS Outlook mail is copy/pasted into RadRichTextBox. 

This is reproducible in Paged LayoutMode.

Inserting a page break inside a table is currently not supported (the feature request is logged at https://feedback.telerik.com/Project/143/Feedback/Details/211108). Therefore, the Page Break button inside the Insert tab of the ribbon should be disabled when the caret is positioned inside a table.

Workaround: Track the position of the caret and when the latter goes into a table, set the Enabled property of InsertPageBreakCommand to false.

Expose an API allowing easy customization of the layer.

Currently, CopyHyperlink command (Context menu over hyperlink -> Copy Hyperlink) puts hyperlink text in plain text format in the clipboard. Instead, it should put the URI. This way when the user pastes in a plaint text editor, they will get the URI.

Workaround: The user could copy the text from the Edit Hyperlink dialog instead. 

Currently, when the users perform replace, and there are no more matches which should be replaced, the "The searched text was not found" message is shown. Add functionality to say that there are no more matches instead of saying that the text is not found.

When an RTF document contains table inside table in the header or in the footer, the document cannot be imported due to NullReferenceException. In the case of RadRichTextBox the exception is handled, but it's not when RtfFormatProvider is used directly.

The bug is regression in 2016 R3.

The issue is reproduced with Marathi IME. Type some letters, press and release shift, then press space. The result is that the current IME text is duplicated. 

When document model is used in multi-threaded scenario, all image sources need to be frozen. Expose a method that does that out of the box.

Workaround: Solution with the public API available is in the attached freezeImagesInRadDocument.zip. 

The TableCellProperty.Padding property of the "TableNormal" StyleDefinition doesn't take effect in the UI. The same is valid for the TableProperties.CellPadding property.

To work this around, you can manually set the Padding property of all TableCell elements in the RadDocument.

 var cells = radDocument.EnumerateChildrenOfType<Telerik.Windows.Documents.Model.TableCell>();
 foreach (var cell in cells)
 {
     cell.Padding = new Padding(10);
 }