如何覆盖文档查看器图标以在Plone中以全屏模式查看？

Where exactly can I override the collective.documentviewer code to disable the icon to view the document full screen in another window? Actually when I only click on the 'customize' button for the documentviewer in zcml it throws up an exception for 'widget', even without addition of a letter of code there and the viewer crashes.I am using version 2.2.1 for collective.documentviewer and Plone 4.1.4 on linux. Please guide.Where exactly can I override the collective.doc