StyledText.Text
From Xojo Documentation
Method
The text whose style attributes are managed via the instance of this class.
Notes
The Start and Index parameters of the methods of this class are zero-based and referenced from the start of Text. Set the value of Text using the assignment operator.
Example
Add some styled text to a TextArea:
TextArea1.StyledText.Value = "Hello, World!"
TextArea1.StyledText.Bold(7, 5) = True // "World" is now bold
TextArea1.StyledText.Bold(7, 5) = True // "World" is now bold