accept-invite-portlet/src/main/webapp/WEB-INF/liferay-display.xml

<?xml version="1.0"?>
<!DOCTYPE display PUBLIC "-//Liferay//DTD Display 6.2.0//EN" "http://www.liferay.com/dtd/liferay-display_6_2_0.dtd">

<display>
	<category name="category.sample">
		<portlet id="accept-invite-portlet" />
	</category>
</display>