In code behind, when a user moves the curser in the RadRichTextBox, we check information tagged to span elements. For certain spans, we want the contents to change color, so we set span.ForeColor to a new value, but this doesn't reflect in the UI. I assume there is some update mechanism, but it isn't obvious. I can select the entire span, copy, and paste it in place and it will show the new color, but we want it to happen when a user is moving the cursor.
We're tracking the cursor in the RadDocument.CaretPosition.PositionChanged event handler.