Fix disappearing context menus on RasPi devices

package.nw/gt_roster.html

@@ -374,7 +374,7 @@
         </div>
       </header>
 
-      <main id="RosterTable" oncontextmenu="handleContextMenu(event);"></main>
+      <main id="RosterTable" oncontextmenu="return handleContextMenu(event);"></main>
     </div>
 
     <div