When editing in the Page namespace, most of the times the buttons for Zoom In/Zoom Out/Zoom Reset do not work.
The console says: Uncaught Error: cannot call methods on prpZoom prior to initialization; attempted to call method 'zoomIn'
so it seems the problem is that the methods are not initialized properly on page loading. When this happens, it is also not possible to move the image.
This problem used to happen sporadically in the past, but since 4-5 days it happens very frequently to many users, making it very difficult (and frustrating) to edit pages.