diff --git a/CHANGES.md b/CHANGES.md
index fcec6485e69..4c1903b6453 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -13,6 +13,9 @@ Fixed Issues:
 * [#2756](https://github.com/ckeditor/ckeditor-dev/issues/2756): Fixed: The [Auto Link](https://ckeditor.com/cke4/addon/autolink) plugin causes an error when typing in [Source Editing Mode](https://ckeditor.com/docs/ckeditor4/latest/guide/dev_sourcearea.html).
 * [#1986](https://github.com/ckeditor/ckeditor-dev/issues/1986): Fixed: Cell Properties dialog from [Table Tools](https://ckeditor.com/cke4/addon/tabletools) plugin shows styles that are not allowed through [`config.allowedContent`](https://ckeditor.com/docs/ckeditor4/latest/api/CKEDITOR_config.html#cfg-allowedContent).
 * [#2565](https://github.com/ckeditor/ckeditor-dev/issues/2565): [IE, Edge] Fixed: Buttons in the [Editor Toolbar](https://ckeditor.com/cke4/addon/toolbar) are activated by clicking them with right mouse button.
+* [#2780](https://github.com/ckeditor/ckeditor-dev/issues/2780): Fixed: Undo steps disappears after multiple change of selection.
+* [#2470](https://github.com/ckeditor/ckeditor-dev/issues/2470): [Firefox] Fixed: Widget's nested editable blurred upon focus.
+* [#2655](https://github.com/ckeditor/ckeditor-dev/issues/2655): [Chrome, Safari] Fixed: Widget's nested editable can't be focused under certain circumstances.
 
 ## CKEditor 4.11.2
 
diff --git a/plugins/copyformatting/plugin.js b/plugins/copyformatting/plugin.js
index fb9188a5d76..215aadf56c7 100644
--- a/plugins/copyformatting/plugin.js
+++ b/plugins/copyformatting/plugin.js
@@ -91,7 +91,8 @@
 			} );
 
 			editor.on( 'contentDom', function() {
-				var editable = editor.editable(),
+				var cmd = editor.getCommand( 'copyFormatting' ),
+					editable = editor.editable(),
 					// Host element for apply formatting click. In case of classic element it needs to be entire
 					// document, otherwise clicking in body margins would not trigger the event.
 					// Editors with divarea plugin enabled should be treated like inline one – otherwise
@@ -101,14 +102,13 @@
 					copyFormattingButtonEl;
 
 				editable.attachListener( mouseupHost, 'mouseup', function( evt ) {
-					if ( getMouseButton( evt ) === CKEDITOR.MOUSE_BUTTON_LEFT ) {
+					// Apply formatting only if any styles are copied (#2780, #2655, #2470).
+					if ( getMouseButton( evt ) === CKEDITOR.MOUSE_BUTTON_LEFT && cmd.state === CKEDITOR.TRISTATE_ON ) {
 						editor.execCommand( 'applyFormatting' );
 					}
 				} );
 
 				editable.attachListener( CKEDITOR.document, 'mouseup', function( evt ) {
-					var cmd = editor.getCommand( 'copyFormatting' );
-
 					if ( getMouseButton( evt ) === CKEDITOR.MOUSE_BUTTON_LEFT && cmd.state === CKEDITOR.TRISTATE_ON &&
 						!editable.contains( evt.data.getTarget() ) ) {
 						editor.execCommand( 'copyFormatting' );
@@ -424,10 +424,7 @@
 						documentElement = CKEDITOR.document.getDocumentElement(),
 						isApplied;
 
-					if ( !isFromKeystroke && cmd.state !== CKEDITOR.TRISTATE_ON ) {
-						return;
-
-					} else if ( isFromKeystroke && !copyFormatting.styles ) {
+					if ( isFromKeystroke && !copyFormatting.styles ) {
 						plugin._putScreenReaderMessage( editor, 'failed' );
 						plugin._detachPasteKeystrokeHandler( editor );
 						return false;
diff --git a/tests/plugins/copyformatting/applyformat.js b/tests/plugins/copyformatting/applyformat.js
index bac9abdace6..d867a56800f 100644
--- a/tests/plugins/copyformatting/applyformat.js
+++ b/tests/plugins/copyformatting/applyformat.js
@@ -437,6 +437,21 @@
 
 			bender.tools.selection.setWithHtml( editor, '<table><tr><td>Ce{ll 1</td></tr><tr><td>Ce}ll 2</td></tr></table>' );
 			assert.areSame( tableConstant, determineContext(), 'Selection within two rows' );
+		},
+
+		// (#2780, #2655, #2470)
+		'test applyFormat not fired without copied styles': function() {
+			var editor = this.editor,
+				spy = sinon.spy( editor, 'execCommand' ),
+				isIe8 = CKEDITOR.env.ie && CKEDITOR.env.version < 9;
+
+			editor.document.fire( 'mouseup', new CKEDITOR.dom.event( {
+				button: isIe8 ? 1 : CKEDITOR.MOUSE_BUTTON_LEFT,
+				target: editor.editable()
+			} ) );
+			spy.restore();
+
+			assert.areSame( 0, spy.callCount );
 		}
 	} );
 }() );
diff --git a/tests/plugins/copyformatting/manual/nestededitablefocus.html b/tests/plugins/copyformatting/manual/nestededitablefocus.html
new file mode 100644
index 00000000000..b5ab0a9dd77
--- /dev/null
+++ b/tests/plugins/copyformatting/manual/nestededitablefocus.html
@@ -0,0 +1,64 @@
+<style>
+#square {
+	margin-top: 20px;
+	width: 100px;
+	height: 100px;
+	border: 1px #000 solid;
+	background-color: red;
+}
+</style>
+<h2>Classic editor</h2>
+<div id="classic">
+		<div class="test1">x<div class="content">Widget1</div>y</div>
+</div>
+
+<div id="square"></div>
+
+<script>
+	CKEDITOR.addCss( '.cke_editable { margin: 0; padding: 50px; }' +
+		'.test1 { border: 1px #000 solid; }' );
+	CKEDITOR.replace( 'classic', {
+		extraPlugins: 'test1'
+	} );
+
+	CKEDITOR.plugins.add( 'test1', {
+		requires: 'widget',
+		init: function( editor ) {
+			editor.widgets.add( 'test1', {
+				button: 'Create autoparagraph test',
+				pathName: 'test-widget',
+
+				template:
+					'<div class="test1">' +
+						'<div class="content"></div>' +
+					'</div>',
+
+				editables: {
+					content: {
+						selector: '.content',
+						allowedContent: 'br'
+					}
+				},
+
+				allowedContent: 'div(test1,content)',
+				requiredContent: 'div(test1)',
+
+				upcast: function( element ) {
+					return element.name == 'div' && element.hasClass( 'test1' );
+				},
+
+				init: function() {
+					var square = CKEDITOR.document.getById( 'square' );
+
+					this.editables.content.on( 'focus', function() {
+						square.setStyle( 'background-color', 'green' );
+					} );
+					this.editables.content.on( 'blur', function() {
+						square.setStyle( 'background-color', 'red' );
+					} );
+				}
+
+			} );
+		}
+	} );
+</script>
diff --git a/tests/plugins/copyformatting/manual/nestededitablefocus.md b/tests/plugins/copyformatting/manual/nestededitablefocus.md
new file mode 100644
index 00000000000..d2defacb6b6
--- /dev/null
+++ b/tests/plugins/copyformatting/manual/nestededitablefocus.md
@@ -0,0 +1,17 @@
+@bender-tags: bug, 4.11.3, 2655, 2470
+@bender-ui: collapsed
+@bender-ckeditor-plugins: widget, wysiwygarea, copyformatting
+
+1. Click inside "Widget 1" text to focus nested editable.
+2. Click above the widget (above the black border).
+3. Click once more inside "Widget 1" text.
+
+## Expected
+
+* Focus is moved into nested editable and stays there.
+* Square under the editor is green.
+
+## Unexpected
+
+* Focus is moved into nested editable for a fraction of second and then disappears.
+* Square under the editor is red.
diff --git a/tests/plugins/copyformatting/manual/undointegration.html b/tests/plugins/copyformatting/manual/undointegration.html
new file mode 100644
index 00000000000..e584bf6c76f
--- /dev/null
+++ b/tests/plugins/copyformatting/manual/undointegration.html
@@ -0,0 +1,16 @@
+<h2>First editor</h2>
+<div id="editor1" contenteditable="true">
+	<p><strong><u><span style="color: #f00;" class="important">Apollo 11</span></u></strong> <s>was the</s> <span style="color: #f00;" class="important">spaceflight</span> that landed the first humans, Americans <a href="http://en.wikipedia.org/wiki/Neil_Armstrong" title="Neil Armstrong">Neil Armstrong</a> and <a href="http://en.wikipedia.org/wiki/Buzz_Aldrin" title="Buzz Aldrin">Buzz Aldrin</a>, on the Moon on July 20, 1969, at 20:18 UTC. <span style="background-color: #f00;" bogus-attr="2">Armstrong</span> became the first to step onto the lunar surface 6 hours later on July 21 at 02:56 UTC.</p>
+</div>
+
+<h2>Second editor</h2>
+<div id="editor2" contenteditable="true">
+	<p><strong><u><span style="color: #f00;" class="important">Apollo 11</span></u></strong> <s>was the</s> <span style="color: #f00;" class="important">spaceflight</span> that landed the first humans, Americans <a href="http://en.wikipedia.org/wiki/Neil_Armstrong" title="Neil Armstrong">Neil Armstrong</a> and <a href="http://en.wikipedia.org/wiki/Buzz_Aldrin" title="Buzz Aldrin">Buzz Aldrin</a>, on the Moon on July 20, 1969, at 20:18 UTC. <span style="background-color: #f00;" bogus-attr="2">Armstrong</span> became the first to step onto the lunar surface 6 hours later on July 21 at 02:56 UTC.</p>
+</div>
+
+<script>
+	CKEDITOR.replace( 'editor1' );
+	CKEDITOR.replace( 'editor2', {
+		extraPlugins: 'divarea'
+	} );
+</script>
diff --git a/tests/plugins/copyformatting/manual/undointegration.md b/tests/plugins/copyformatting/manual/undointegration.md
new file mode 100644
index 00000000000..add98940eb2
--- /dev/null
+++ b/tests/plugins/copyformatting/manual/undointegration.md
@@ -0,0 +1,20 @@
+@bender-ui: collapsed
+@bender-tags: bug, copyformatting, 4.11.3, 2780
+@bender-ckeditor-plugins: copyformatting, toolbar, wysiwygarea, undo, basicstyles
+
+## Test both editors
+1. Add some content to editor (e.g. new line), to "activate" undo step.
+2. Start to click around editor to change selection inside editor (20-25 times). Selection **have to differ** between adjacent steps.
+
+  ### Expected:
+  Undo UI button is active.
+  ### Unexpected:
+  Undo UI became disabled.
+
+3. Click undo button to revert change made in point 1. Make sure that Redo button is activated.
+4. Make new selection inside editor.
+
+  ### Expected:
+  Redo UI button is active.
+  ### Unexpected:
+  Redo UI button became disabled.
diff --git a/tests/plugins/copyformatting/undointegration.js b/tests/plugins/copyformatting/undointegration.js
new file mode 100644
index 00000000000..8e65b21a934
--- /dev/null
+++ b/tests/plugins/copyformatting/undointegration.js
@@ -0,0 +1,71 @@
+/* bender-tags: copyformatting */
+/* bender-ckeditor-plugins: wysiwygarea, toolbar, copyformatting, undo */
+/* bender-ui: collapsed */
+
+( function() {
+	'use strict';
+
+	var leftMouseButton = CKEDITOR.env.ie && CKEDITOR.env.version < 9 ? 1 : CKEDITOR.MOUSE_BUTTON_LEFT;
+
+	bender.editor = {
+		config: {
+			allowedContent: true
+		}
+	};
+
+
+	bender.test( {
+		// (#2780)
+		'test basic undo integration': function() {
+			var editor = this.editor,
+				bot = this.editorBot,
+				sel = editor.getSelection(),
+				spans;
+
+			resetUndoAndCreateFirstSnapshot( bot );
+
+			spans = editor.editable().find( 'span' );
+			for ( var i = 0; i < editor.undoManager.limit; i++ ) {
+				sel.selectElement( spans.getItem( i % 2 ) );
+				editor.document.fire( 'mouseup', new CKEDITOR.dom.event( {
+					button: leftMouseButton,
+					target: editor.editable()
+				} ) );
+			}
+
+			assert.areSame( 1, editor.undoManager.index, 'There shouldn\'t be new undo steps and editor should remain on the 1st step.' );
+			assert.isTrue( editor.undoManager.undoable(), 'Editor should have a possibility to undo.' );
+		},
+		// (#2780)
+		'test basic redo integration': function() {
+			var editor = this.editor,
+				bot = this.editorBot,
+				sel = editor.getSelection();
+
+			resetUndoAndCreateFirstSnapshot( bot );
+
+			bot.execCommand( 'undo' );
+
+			sel.selectElement( editor.editable().find( 'span' ).getItem( 0 ) );
+			editor.document.fire( 'mouseup', new CKEDITOR.dom.event( {
+				button: leftMouseButton,
+				target: editor.editable()
+			} ) );
+
+			assert.isTrue( editor.undoManager.redoable(), 'Editor should has possibility to redo.' );
+		}
+	} );
+
+	function resetUndoAndCreateFirstSnapshot( bot ) {
+		var editor = bot.editor;
+
+		bot.setHtmlWithSelection( '<p><span>foo</span> []bar <span>baz</span></p>' );
+
+		editor.undoManager.reset();
+		editor.fire( 'saveSnapshot' );
+
+		editor.insertText( '1' );
+		editor.fire( 'saveSnapshot' );
+	}
+
+} )();