When showing the document in RadRichTextBox we don't recommend to make direct changes over the elements. For this purpose, you could use the RadDocumentEditor
class, which is intended for similar scenarios and triggers important updates after the modifications.
It is not guaranteed that changing the font size of a Span, part of the field, will call the CopyPropertiesFrom() method. Setting the FontSize of the span will change the size of the font of the result
fragment of the field and in order to keep the settings, they should be applied to the code field. This is automatically done by the command used from the UI and by the methods of RadDocumentEditor. You could check how I modified the code-snippet. It selects the first row of a Table and changes its FontSize:
TableRow row =
DocumentPosition start =
DocumentPosition end =
RadDocumentEditor editor =
Hope this helps.
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