When using NB2, I can't see any way of zooming into the PDF text being annotated independently of zooming the whole browser window. (I am using Chrome on a MacBook Pro). The problems with zooming the whole window are that:
(i) it causes the right-hand edge of the PDF text to be cut off by the maximum annotation panel boundary;
(ii) the bottom of the annotation panel drops out of sight, making it impossible to complete submission of an annotation.
The ability to enlarge the text being annotated without loss of functionality is an important accessibility feature.