Thanks for the question regarding the zoom panel.
I'm not able to see an attachment, would you be able to reply with the screenshot so I can look more into the issue?
Additionally, if you are able to provide any more information about confirming the issue on the demo site + PDFTron that would be helpful in terms of letting us reproduce the problem. Specifically, if you can link to a demo page where you experienced the issue and some reproduction steps (or a screenshot showing the issue would work as well).
PDFTron Systems, Inc.
CONFIDENTIALITY NOTICE: This message (and any attachment to it) is intended only for the use of the individual or entity to which it is addressed in the header, and may contain information that is privileged, confidential and exempt from disclosure under applicable law. Any reproduction, distribution, modification or use of the contents of this message (and any attachment to it) by any individual or entity other than the intended recipient is prohibited. If you have received this communication in error, please notify us immediately and delete the original.