Merge branch 't/9761'

Author: oleq

CHANGES.md

@@ -4,6 +4,7 @@ CKEditor 4 Changelog
 ## CKEditor 4.1.2
 
 * [#10389](http://dev.ckeditor.com/ticket/10389): Invalid closing tag </tr> in a sample "Text and Table" template.
+* [#9761](http://dev.ckeditor.com/ticket/9761): Update BACKSPACE key state in blockedKeystrokes when using editor.setReadOnly().
 
 ## CKEditor 4.1.1
 

core/editable.js

@@ -432,7 +432,11 @@
 
 				// Setup editor keystroke handlers on this element.
 				var keystrokeHandler = editor.keystrokeHandler;
-				keystrokeHandler.blockedKeystrokes[ 8 ] = editor.readOnly;
+
+				// If editor is read-only, then make sure that BACKSPACE key
+				// is blocked to prevent browser history navigation.
+				keystrokeHandler.blockedKeystrokes[ 8 ] = +editor.readOnly;
+
 				editor.keystrokeHandler.attach( this );
 
 				// Update focus states.

core/editor.js

@@ -840,6 +840,10 @@
 			if ( this.readOnly != isReadOnly ) {
 				this.readOnly = isReadOnly;
 
+				// Block or release BACKSPACE key according to current read-only
+				// state to prevent browser's history navigation (#9761).
+				this.keystrokeHandler.blockedKeystrokes[ 8 ] = +isReadOnly;
+
 				this.editable().setReadOnly( isReadOnly );
 
 				// Fire the readOnly event so the editor features can update