BuddyPress.org

Yes, the other one is this:

<div class="item-list-tabs" id="subnav" aria-label="Navigazione gruppo secondaria" role="navigation">
	<ul>
		<li class="groups-members-search" role="search">
			<form action="" method="get" id="search-members-form">
				<label for="members_search"><input type="text" name="members_search" id="members_search" placeholder="Cerca membri..."></label>
				<input type="submit" id="members_search_submit" name="members_search_submit" value="Cerca">
			</form>	
		</li>

		<li id="group_members-order-select" class="last filter">
			<label for="group_members-order-by">Ordinato per:</label>
			<select id="group_members-order-by">
				<option value="last_joined">Nuovi</option>
				<option value="first_joined">Il più vecchio</option>
				<option value="alphabetical">Alfabetico</option>
			</select>
		</li>		
	</ul>
</div>

and includes the search form.