I am using Outlook Web mail (through Windows Live) for work. Some of the Outlook pages have their own context menus enabled, but when I right-click on, e.g., an email in my inbox, the native Firefox context menu pops up over the Outlook page's context menu. I can see the border of the Outlook context menu underneath but cannot access its options. I'd like to disable Firefox's context menu on that site alone. Thank you.