1 files changed, 32 insertions, 0 deletions
diff --git a/browser/modules/SelectionChangedMenulist.jsm b/browser/modules/SelectionChangedMenulist.jsm
new file mode 100644
index 0000000000..7fcae982cc
--- /dev/null
+++ b/browser/modules/SelectionChangedMenulist.jsm
@@ -0,0 +1,32 @@
+/* - This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this file,
+   - You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+var EXPORTED_SYMBOLS = ["SelectionChangedMenulist"];
+
+class SelectionChangedMenulist {
+  // A menulist wrapper that will open the popup when navigating with the
+  // keyboard on Windows and trigger the provided handler when the popup
+  // is hiding. This matches the behaviour of MacOS and Linux more closely.
+
+  constructor(menulist, onCommand) {
+    let popup = menulist.menupopup;
+    let lastEvent;
+
+    menulist.addEventListener("command", event => {
+      lastEvent = event;
+      if (popup.state != "open" && popup.state != "showing") {
+        popup.openPopup();
+      }
+    });
+
+    popup.addEventListener("popuphiding", () => {
+      if (lastEvent) {
+        onCommand(lastEvent);
+        lastEvent = null;
+      }
+    });
+  }
+}