From c65f41dfbd7671ab15b64f9bb6a2c3c30fd1da1f Mon Sep 17 00:00:00 2001
From: CezaryKulakowski <50166166+CezaryKulakowski@users.noreply.github.com>
Date: Mon, 13 Apr 2020 10:25:55 +0200
Subject: [PATCH] fix: don't assign NSAlert to window which is not visible
 (#22672)

* fix: don't assign NSAlert to window which is not visible

Without this change it's possible to create message box which can't
be dismissed on mac.

* fixup! fix: don't assign NSAlert to window which is not visible

* fixup! fix: don't assign NSAlert to window which is not visible
---
 docs/api/dialog.md                  | 1 +
 shell/browser/ui/message_box_mac.mm | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/docs/api/dialog.md b/docs/api/dialog.md
index 678700a58600..c3903ce73af6 100644
--- a/docs/api/dialog.md
+++ b/docs/api/dialog.md
@@ -269,6 +269,7 @@ Shows a message box, it will block the process until the message box is closed.
 It returns the index of the clicked button.
 
 The `browserWindow` argument allows the dialog to attach itself to a parent window, making it modal.
+If `browserWindow` is not shown dialog will not be attached to it. In such case It will be displayed as independed window.
 
 ### `dialog.showMessageBox([browserWindow, ]options)`
 
diff --git a/shell/browser/ui/message_box_mac.mm b/shell/browser/ui/message_box_mac.mm
index cdfc4797f990..63820e6e3167 100644
--- a/shell/browser/ui/message_box_mac.mm
+++ b/shell/browser/ui/message_box_mac.mm
@@ -97,8 +97,10 @@ int ShowMessageBoxSync(const MessageBoxSettings& settings) {
   NSAlert* alert = CreateNSAlert(settings);
 
   // Use runModal for synchronous alert without parent, since we don't have a
-  // window to wait for.
-  if (!settings.parent_window)
+  // window to wait for. Also use it when window is provided but it is not
+  // shown as it would be impossible to dismiss the alert if it is connected
+  // to invisible window (see #22671).
+  if (!settings.parent_window || !settings.parent_window->IsVisible())
     return [[alert autorelease] runModal];
 
   __block int ret_code = -1;