From 92a292d5fb043ef84d017cd3e9be83b79fde25a9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Piotrek=20Koszuli=C5=84ski?= <pkoszulinski@gmail.com>
Date: Thu, 18 Jan 2018 11:45:47 +0100
Subject: [PATCH 1/4] Focus the new editing host to workaround FF's errors.

---
 src/view/renderer.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/view/renderer.js b/src/view/renderer.js
index fe915e44c..10e7ef4f9 100644
--- a/src/view/renderer.js
+++ b/src/view/renderer.js
@@ -628,6 +628,10 @@ export default class Renderer {
 		const anchor = this.domConverter.viewPositionToDom( this.selection.anchor );
 		const focus = this.domConverter.viewPositionToDom( this.selection.focus );
 
+		// Focus the new editing host.
+		// Otherwise, FF may throw an error (https://github.com/ckeditor/ckeditor5/issues/721).
+		domRoot.focus();
+
 		domSelection.collapse( anchor.parent, anchor.offset );
 		domSelection.extend( focus.parent, focus.offset );
 	}

From c1b2e32482a819dc82affb2e23b15ecde2540d9c Mon Sep 17 00:00:00 2001
From: Maciej Bukowski <ma2ciek@gmail.com>
Date: Tue, 13 Feb 2018 14:11:40 +0100
Subject: [PATCH 2/4] Added manual test for ckeditor5#721.

---
 tests/manual/tickets/721/1.html |  3 ++
 tests/manual/tickets/721/1.js   | 67 +++++++++++++++++++++++++++++++++
 tests/manual/tickets/721/1.md   | 11 ++++++
 3 files changed, 81 insertions(+)
 create mode 100644 tests/manual/tickets/721/1.html
 create mode 100644 tests/manual/tickets/721/1.js
 create mode 100644 tests/manual/tickets/721/1.md

diff --git a/tests/manual/tickets/721/1.html b/tests/manual/tickets/721/1.html
new file mode 100644
index 000000000..bf383218e
--- /dev/null
+++ b/tests/manual/tickets/721/1.html
@@ -0,0 +1,3 @@
+<div id="editor">
+	<p>This is an <strong>editor</strong> instance.</p>
+</div>
diff --git a/tests/manual/tickets/721/1.js b/tests/manual/tickets/721/1.js
new file mode 100644
index 000000000..8e3946c69
--- /dev/null
+++ b/tests/manual/tickets/721/1.js
@@ -0,0 +1,67 @@
+/**
+ * @license Copyright (c) 2003-2018, CKSource - Frederico Knabben. All rights reserved.
+ * For licensing, see LICENSE.md.
+ */
+
+/* globals console, window, document */
+
+import ClassicEditor from '@ckeditor/ckeditor5-editor-classic/src/classiceditor';
+import Essentials from '@ckeditor/ckeditor5-essentials/src/essentials';
+import Paragraph from '@ckeditor/ckeditor5-paragraph/src/paragraph';
+import Bold from '@ckeditor/ckeditor5-basic-styles/src/bold';
+import { toWidget } from '@ckeditor/ckeditor5-widget/src/utils';
+import Widget from '@ckeditor/ckeditor5-widget/src/widget';
+
+import AttributeContainer from '../../../../src/view/attributeelement';
+import ViewContainer from '../../../../src/view/containerelement';
+import { downcastElementToElement } from '../../../../src/conversion/downcast-converters';
+import { setData } from '../../../../src/dev-utils/model';
+import ViewEditable from '../../../../src/view/editableelement';
+
+ClassicEditor
+	.create( document.querySelector( '#editor' ), {
+		plugins: [ Essentials, Paragraph, Bold, Widget ],
+		toolbar: [ 'undo', 'redo' ]
+	} )
+	.then( editor => {
+		window.editor = editor;
+
+		const model = editor.model;
+
+		model.schema.register( 'widget', {
+			inheritAllFrom: '$block',
+			isObject: true
+		} );
+
+		model.schema.extend( '$text', {
+			allowIn: 'nested'
+		} );
+
+		model.schema.register( 'nested', {
+			allowIn: 'widget',
+			isLimit: true
+		} );
+
+		editor.conversion.for( 'downcast' )
+			.add( downcastElementToElement( {
+				model: 'widget',
+				view: () => {
+					const b = new AttributeContainer( 'b' );
+					const div = new ViewContainer( 'div', null, b );
+
+					return toWidget( div, { label: 'element label' } );
+				}
+			} ) )
+			.add( downcastElementToElement( {
+				model: 'nested',
+				view: () => new ViewEditable( 'figcaption', { contenteditable: true } )
+			} ) );
+
+		setData( editor.model,
+			'<paragraph>foo[]</paragraph>' +
+			'<widget><nested>bar</nested></widget>'
+		);
+	} )
+	.catch( err => {
+		console.error( err.stack );
+	} );
diff --git a/tests/manual/tickets/721/1.md b/tests/manual/tickets/721/1.md
new file mode 100644
index 000000000..de8d353bf
--- /dev/null
+++ b/tests/manual/tickets/721/1.md
@@ -0,0 +1,11 @@
+## Renderer should handle nested editables [FF] <a href="https://github.com/ckeditor/ckeditor5/issues/721">ckeditor5#721</a>
+
+1. Put the caret in the first paragraph and type something.
+1. Put the caret inside the widget (where is `bar` already).
+1. Click `Undo`.
+
+**Expected**:
+
+No error in the console.
+
+

From 58b6dea1baa72c56a711986c5f553ca8ac61c1a9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Piotrek=20Koszuli=C5=84ski?= <pkoszulinski@gmail.com>
Date: Tue, 13 Feb 2018 16:29:36 +0100
Subject: [PATCH 3/4] Extended the manual test.

---
 tests/manual/tickets/721/1.html | 6 ++++++
 tests/manual/tickets/721/1.js   | 3 ++-
 tests/manual/tickets/721/1.md   | 9 +++++++--
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/tests/manual/tickets/721/1.html b/tests/manual/tickets/721/1.html
index bf383218e..f3a6d6e16 100644
--- a/tests/manual/tickets/721/1.html
+++ b/tests/manual/tickets/721/1.html
@@ -1,3 +1,9 @@
+<style>
+	.ck-widget {
+		border: solid 3px blue;
+	}
+</style>
+
 <div id="editor">
 	<p>This is an <strong>editor</strong> instance.</p>
 </div>
diff --git a/tests/manual/tickets/721/1.js b/tests/manual/tickets/721/1.js
index 8e3946c69..1a5c1c7e7 100644
--- a/tests/manual/tickets/721/1.js
+++ b/tests/manual/tickets/721/1.js
@@ -59,7 +59,8 @@ ClassicEditor
 
 		setData( editor.model,
 			'<paragraph>foo[]</paragraph>' +
-			'<widget><nested>bar</nested></widget>'
+			'<widget><nested>bar</nested></widget>' +
+			'<widget><nested>bom</nested></widget>'
 		);
 	} )
 	.catch( err => {
diff --git a/tests/manual/tickets/721/1.md b/tests/manual/tickets/721/1.md
index de8d353bf..00425e7c0 100644
--- a/tests/manual/tickets/721/1.md
+++ b/tests/manual/tickets/721/1.md
@@ -1,11 +1,16 @@
 ## Renderer should handle nested editables [FF] <a href="https://github.com/ckeditor/ckeditor5/issues/721">ckeditor5#721</a>
 
+### TC1
+
 1. Put the caret in the first paragraph and type something.
-1. Put the caret inside the widget (where is `bar` already).
-1. Click `Undo`.
+1. Put the caret inside the widget (in "bar").
+1. Click "Undo" or press <kbd>Ctrl</kbd>+<kbd>Z</kbd> (check both).
 
 **Expected**:
 
 No error in the console.
 
+### TC2
+
+Try the same TC as above but use both nested editables. See if the focus is correctly moved between them.
 

From 3b2737e4475b805a49af0919e2f16e9ef04f8a4a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Piotrek=20Koszuli=C5=84ski?= <pkoszulinski@gmail.com>
Date: Tue, 13 Feb 2018 16:35:49 +0100
Subject: [PATCH 4/4] Moved tests to a directory which indicates that this is
 ckeditor5#721.

---
 tests/manual/tickets/{721 => ckeditor5-721}/1.html | 0
 tests/manual/tickets/{721 => ckeditor5-721}/1.js   | 0
 tests/manual/tickets/{721 => ckeditor5-721}/1.md   | 0
 3 files changed, 0 insertions(+), 0 deletions(-)
 rename tests/manual/tickets/{721 => ckeditor5-721}/1.html (100%)
 rename tests/manual/tickets/{721 => ckeditor5-721}/1.js (100%)
 rename tests/manual/tickets/{721 => ckeditor5-721}/1.md (100%)

diff --git a/tests/manual/tickets/721/1.html b/tests/manual/tickets/ckeditor5-721/1.html
similarity index 100%
rename from tests/manual/tickets/721/1.html
rename to tests/manual/tickets/ckeditor5-721/1.html
diff --git a/tests/manual/tickets/721/1.js b/tests/manual/tickets/ckeditor5-721/1.js
similarity index 100%
rename from tests/manual/tickets/721/1.js
rename to tests/manual/tickets/ckeditor5-721/1.js
diff --git a/tests/manual/tickets/721/1.md b/tests/manual/tickets/ckeditor5-721/1.md
similarity index 100%
rename from tests/manual/tickets/721/1.md
rename to tests/manual/tickets/ckeditor5-721/1.md