You're using the Chromebook machine with Viewer, correct? If this is the case, please note that we do not provide official support for Chromebook-based devices as of yet. However, Chromebook users can use our Viewer for Android which, unfortunately, currently has somewhat limited features. While we do not have plans for releasing Viewer for Chromebook OS, hopefully, we'll be able to release improved mobile Viewer in the near future with more robust features. Sorry for the inconvenience.