changed next() to find() in Treeview toggle()

build/js/Treeview.js

@@ -87,15 +87,15 @@ const Treeview = (($) => {
     }
 
     toggle(event) {
+      event.preventDefault()
+
       const $relativeTarget = $(event.currentTarget)
-      const treeviewMenu    = $relativeTarget.next()
+      const treeviewMenu    = $relativeTarget.parents(Selector.LI).find(Selector.TREEVIEW_MENU)
 
       if (!treeviewMenu.is(Selector.TREEVIEW_MENU)) {
         return
       }
 
-      event.preventDefault()
-
       const parentLi = $relativeTarget.parents(Selector.LI).first()
       const isOpen   = parentLi.hasClass(ClassName.OPEN)