Try to highlight the text Online Demo in the demo app and you will see that last character is only partially highlighted
Could you please a more detailed description? Including a screenshot would be useful.
Pls see the attached image specifically, Online Demo, which I am trying to highlight. Pls notice that o is not completely highlighted.
To replicate, you can simply run the demo program provided.
Text position bugs are a function of the PDF.js open source core, which we do not support.