From f2d172de7d3820b83721bf73aa3bbc83f9f5e07e Mon Sep 17 00:00:00 2001
From: djmaze <djmaze@djmaze.lan>
Date: Tue, 31 Aug 2021 16:17:20 +0200
Subject: [PATCH] Prevent unloading of browser window when popups (like
 composer window) are open.

---
 dev/App/User.js    | 3 ++-
 dev/Knoin/Knoin.js | 5 +++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/dev/App/User.js b/dev/App/User.js
index 8322b0ae4..9cdf59014 100644
--- a/dev/App/User.js
+++ b/dev/App/User.js
@@ -72,7 +72,7 @@ import { LoginUserScreen } from 'Screen/User/Login';
 import { MailBoxUserScreen } from 'Screen/User/MailBox';
 import { SettingsUserScreen } from 'Screen/User/Settings';
 
-import { startScreens, showScreenPopup } from 'Knoin/Knoin';
+import { startScreens, showScreenPopup, arePopupsVisible } from 'Knoin/Knoin';
 
 import { AbstractApp } from 'App/Abstract';
 
@@ -851,6 +851,7 @@ class AppUser extends AbstractApp {
 		super.bootstart();
 
 		addEventListener('resize', () => leftPanelDisabled(ThemeStore.isMobile() || 1000 > innerWidth));
+		addEventListener('beforeunload', event => arePopupsVisible() && event.preventDefault() , {capture: true});
 
 		NotificationUserStore.populate();
 		AccountUserStore.populate();
diff --git a/dev/Knoin/Knoin.js b/dev/Knoin/Knoin.js
index 36d0c6e81..e8f0ce45d 100644
--- a/dev/Knoin/Knoin.js
+++ b/dev/Knoin/Knoin.js
@@ -4,6 +4,7 @@ import { doc, $htmlCL } from 'Common/Globals';
 import { arrayLength, isFunction } from 'Common/Utils';
 
 let currentScreen = null,
+	popupsVisible = 0,
 	defaultScreenName = '';
 
 const SCREENS = {},
@@ -60,6 +61,7 @@ const SCREENS = {},
 
 					vm.modalVisibility.subscribe(value => {
 						if (value) {
+							++popupsVisible;
 							vmDom.style.zIndex = 3000 + popupVisibilityNames().length + 10;
 							vmDom.hidden = false;
 							vm.storeAndSetScope();
@@ -69,6 +71,7 @@ const SCREENS = {},
 								vmDom.classList.add('show'); // trigger the transitions
 							});
 						} else {
+							popupsVisible = Math.max(0, popupsVisible-1);
 							vm.onHide && vm.onHide();
 							vmDom.classList.remove('show');
 							vm.restoreScope();
@@ -268,6 +271,8 @@ export const
 		}
 	},
 
+	arePopupsVisible = () => 0 < popupsVisible,
+
 	/**
 	 * @param {Function} ViewModelClassToShow
 	 * @returns {boolean}