Right clicking on an image displayed using the gallery macro doesn't always trigger the image context menu

This happens when you right click on the middle of the image. As a consequence, users can be misled into thinking they can't copy an image from the gallery. The problem is that the gallery macro ( http://extensions.xwiki.org/xwiki/bin/view/Extension/Gallery+Macro ) displays the DIV with the navigation arrows on top of the image.