From 368ee51d86c337c8e0d0fd78f70be078908ffb75 Mon Sep 17 00:00:00 2001
From: Moonchild <moonchild@palemoon.org>
Date: Sat, 15 Jun 2024 12:33:06 +0200
Subject: [PATCH] Issue #2532 - Don't do PreventDefault for escape key if
 <select> dropdown is not shown

We always use PreventDefault for <select> element, which is problematic if modal
dialog is on as it prevents cancelling the dialog. We fix it by not blocking the
default action if <select> is not shown.

See Bug 1649278
---
 layout/forms/nsListControlFrame.cpp | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/layout/forms/nsListControlFrame.cpp b/layout/forms/nsListControlFrame.cpp
index 4daa470a9e..0f6772a09a 100644
--- a/layout/forms/nsListControlFrame.cpp
+++ b/layout/forms/nsListControlFrame.cpp
@@ -2236,11 +2236,20 @@ nsListControlFrame::KeyDown(nsIDOMEvent* aKeyEvent)
         return NS_OK;
       }
 
+      // We don't want to preventDefault for escape key if the dropdown
+      // popup is not shown.
+      // Need to do the check before AboutToRollup because AboutToRollup
+      // may update the dropdown flags.
+      bool doPreventDefault =
+          !mComboboxFrame || mComboboxFrame->IsDroppedDownOrHasParentPopup();
+
       AboutToRollup();
-      // If the select element is a dropdown style, Enter key should be
+      // If the select element is a dropdown style, Escape key should be
       // consumed everytime since Escape key may be pressed accidentally after
       // the dropdown is closed by Escepe key.
-      aKeyEvent->PreventDefault();
+      if (doPreventDefault) {
+        aKeyEvent->PreventDefault();
+      }
       return NS_OK;
     }
     case NS_VK_PAGE_UP: {