Jira Plugin: Conditions in atlassian-plugin.xml don't work

Jira Development Jira Server
1

I have a plugin that works perfectly fine until I add conditions in a web-item tag:

The condition class looks exactly like the solution of this post

my web-item tag looks like this

	<web-item key="xx_link" name="Link to XX Servlet"
		section="system.top.navigation.bar" weight="47">
		<conditions type="OR">
			<condition
				class="de.yy.jiraplugin.UserInGroupCondition">
				<param name="groupName">Jira_Admins_Test</param>
			</condition>
			<condition
				class="de.yy.jiraplugin.UserInGroupCondition">
				<param name="groupName">Jira_XX</param>
			</condition>
			<condition
				class="de.yy.jiraplugin.UserInGroupCondition">
				<param name="groupName">Jira_XX_Admins</param>
			</condition>
		</conditions>
		<label>XX</label>
		<link linkId="xx_link">/plugins/servlet/xx</link>
	</web-item>