Some gadgets – called singular gadgets – cannot be combined with other singular gadgets on the same page. For example, you cannot combine an events calendar with a photo album on the same page. If a gadget is grayed out, it's because it's a singular gadget and the page you are editing already has a singular gadget.Singular gadgets cannot be added to page templates or system pages.The following gadgets are singular gadgets:BlogDiscussion forumDonation formEvent calendarForum summaryMembership applicationMember directoryPhoto albumSubscription form