From dc43359fc35fedef3faf3bfbc93e020b4b37e1e7 Mon Sep 17 00:00:00 2001
From: Tomas Roun <tomas.roun@cern.ch>
Date: Wed, 28 Sep 2022 15:26:26 +0200
Subject: [PATCH] Stop propagation of keydown events when full screen is active

---
 src/fullscreen.js | 70 +++++++++++++++++++++++++----------------------
 1 file changed, 38 insertions(+), 32 deletions(-)

diff --git a/src/fullscreen.js b/src/fullscreen.js
index d69a748..f90b82b 100644
--- a/src/fullscreen.js
+++ b/src/fullscreen.js
@@ -6,6 +6,24 @@ import {CLOSE_ON_ESCAPE, CLOSE_ON_CLICK} from './config';
 
 import '../theme/fullscreen.css';
 
+let closeOnEscape, closeOnClick, button;
+let isFullScreen = false;
+
+// Close on escape
+const onKeyDown = e => {
+  if (closeOnEscape && e.key === 'Escape' && button && isFullScreen) {
+    // If the full screen mode is active, prevent triggering any other event handler.
+    e.stopPropagation();
+    e.stopImmediatePropagation();
+    button.fire('execute');
+  }
+};
+// Attach the event handler as soon as possible in case the editor
+// is rendered in a modal which can be closed with an escape
+// (or anything else listening for keydown events that we don't want to accidentally trigger).
+// This makes it possible to stop event propagation, which keeps the modal open.
+document.addEventListener('keydown', onKeyDown, {capture: true});
+
 export default class FullScreen extends Plugin {
   static get pluginName() {
     return 'FullScreen';
@@ -25,11 +43,11 @@ export default class FullScreen extends Plugin {
     // Set the default configuration
     editor.config.define(CLOSE_ON_ESCAPE, true);
     editor.config.define(CLOSE_ON_CLICK, true);
+    closeOnEscape = editor.config.get(CLOSE_ON_ESCAPE);
+    closeOnClick = editor.config.get(CLOSE_ON_CLICK);
 
     const maximize = () => {
       const wrapperElement = editor.ui.view.element;
-      // Make the wrapping div focusable so it can capture key presses
-      wrapperElement.setAttribute('tabindex', '0');
       // Apply styles
       wrapperElement.classList.add('ck-plugin-full-screen');
       this.styles = {
@@ -44,55 +62,43 @@ export default class FullScreen extends Plugin {
 
     const minimize = () => {
       const wrapperElement = editor.ui.view.element;
-      wrapperElement.removeAttribute('tabindex');
       wrapperElement.classList.remove('ck-plugin-full-screen');
       editor.editing.view.change(writer => {
         this._restoreStyles(writer, rootElement);
       });
     };
 
-    editor.ui.componentFactory.add('fullscreen', () => {
-      const wrapperElement = editor.ui.view.element;
-      const button = new ButtonView();
-      button.set({
-        label: t('Full screen'),
-        icon: Maximize,
-        tooltip: true,
-      });
-
-      // Make the toolbar button appear clicked when full screen is active
-      button.bind('isOn').to(this, 'isFullScreen');
+    button = new ButtonView();
+    button.set({
+      label: t('Full screen'),
+      icon: Maximize,
+      tooltip: true,
+    });
 
-      const closeOnEscape = editor.config.get(CLOSE_ON_ESCAPE);
-      const closeOnClick = editor.config.get(CLOSE_ON_CLICK);
+    // Make the toolbar button appear clicked when full screen is active
+    button.bind('isOn').to(this, 'isFullScreen');
 
-      // Close on escape
-      const onKeyDown = e => {
-        if (e.key === 'Escape' && this.isFullScreen) {
-          button.fire('execute');
-          e.stopPropagation();
-        }
-      };
+    // Close on background click
+    const onClick = e => {
+      if (e.target === e.currentTarget && this.isFullScreen) {
+        e.stopPropagation();
+        button.fire('execute');
+      }
+    };
 
-      // Close on background click
-      const onClick = e => {
-        if (e.target === e.currentTarget && this.isFullScreen) {
-          button.fire('execute');
-          e.stopPropagation();
-        }
-      };
+    editor.ui.componentFactory.add('fullscreen', () => {
+      const wrapperElement = editor.ui.view.element;
 
       button.on('execute', () => {
         if (!this.isFullScreen) {
-          closeOnEscape && wrapperElement.addEventListener('keydown', onKeyDown);
           closeOnClick && wrapperElement.addEventListener('click', onClick);
           maximize();
         } else {
-          closeOnEscape && wrapperElement.removeEventListener('keydown', onKeyDown);
           closeOnClick && wrapperElement.removeEventListener('click', onClick);
           minimize();
         }
         this.isFullScreen = !this.isFullScreen;
+        isFullScreen = this.isFullScreen;
         editor.editing.view.focus();
       });