use classList `add` instead of `toggle` on show

diff --git a/js/src/dropdown.js b/js/src/dropdown.js
index be561b12822d02036a56dc6b8c6a074506fae140..1e0029a60f978b380a5b64d97980a85c082cf627 100644 (file)
--- a/js/src/dropdown.js
+++ b/js/src/dropdown.js
@@ -184,8 +184,8 @@ class Dropdown extends BaseComponent {
     this._element.focus()
     this._element.setAttribute('aria-expanded', true)
 
-    this._menu.classList.toggle(CLASS_NAME_SHOW)
-    this._element.classList.toggle(CLASS_NAME_SHOW)
+    this._menu.classList.add(CLASS_NAME_SHOW)
+    this._element.classList.add(CLASS_NAME_SHOW)
     EventHandler.trigger(this._element, EVENT_SHOWN, relatedTarget)
   }