First, I just want to thank you for the amazing work you've been doing with openseadragon! I really appreciate the new features you've added over the last couple of years. I just tested my application on a huge touchscreen (more than 60 inch) and it worked. Wonderful.
I did find a problem with Internet Explorer, though. The toolbar buttons aren't working on IE 11 (running on Windows 8.1). I reported this in the issues.