Need the data required to make the symptom appear as well as just the code line(s).
First guess is that the width of the plot area is pretty small and the font size plus bold is pretty large so you're having spacing problems of having sufficient room for what you're trying to display.
Also, if you continually updating this, save the handles of the text objects the first pass and then update the 'String' property each subsequent pass instead of creating another new one with text.
