From Xojo Documentation
Enables you to access the properties and methods of the StyledText class for the text in the TextArea.
If the Styled property is Off then this property returns Nil.
The TextArea must have its MultiLine and Styled properties set to True. The object returned by StyledText is not a copy, so subsequent changes to it will affect the contents of the TextArea. See the example in the section "Using the StyledText Class" in the Notes for the TextArea class.