Import the following code:
<ol>
  <li>Coffee</li>
  <li></li>
  <li>Milk</li>
</ol

Workaround:

public class MyInputBehavior : InputBehavior
{
    public MyInputBehavior(DocumentView view)
        : base(view)
    {
  
    }
  
    public override bool ProcessKeyPress(System.Windows.Forms.KeyPressEventArgs e)
    {
        // TO DO: You code here
        e.KeyChar = char.ToUpper(e.KeyChar);
        return true;
        // By commenting the base call you are supresing the default logic
        //return base.ProcessKeyPress(e);
    }
}

Then you should replace the default input behavior by using the following code snippet:
this.richTextBox.DocumentView.InputBehavior = new MyInputBehavior(this.richTextBox.DocumentView);

IMPROVE. RadRichTextBox - should be able to run with .NET Framework 3.5, rather than 4.0

The equation objects in word document are not copied and imported correctly in RadRichTextBox

RadRichTextBoxElement to be a custom editor of RadGridView

ADD. Export of Office 2010 dotx document templates.

ADD. RadRichTextBox - import text boxes from docx files

Invisible borders in html format are imported as black borders in RadRichTextBox

Resolution: 
This issue is addressed in the new version of the control - RadRichTextEditor. Please use the new control instead the RadRichTextBox. 

Currently it is not possible to control the HTML exported from RadRichTextBox and strip styles or embed them.

Currently this product cannot read the text contained in RichTextBox.