First off may I say how RSyntaxTextArea is such a fantastic, simple and easy piece of software. It does exactly what it says on the tin! Well done you!
I do have a suggestion that could improve the RText API documentation:
* class "HelpDialog" - The comment "// Text field tp type a string to search for." should become "// Text field to type a string to search for.".
and I do have another one that could improve user usability:
* OS Accessibility Settings feeling - Rendering Engine of the project RSyntaxTextArea being able to intercept the text cursor size defined through the Display dialog of the Control Panel > Accessibility module, to retrieve the correct dimension of the cursor in the text area. The same goes for the OS DPI settings (greater dpi should lead to a more magnified view of the text).
This is only a suggestion but I do believe it would improve user usability and make RSyntaxTextArea even greater!