Index: /CKEditor/trunk/CHANGES.html
===================================================================
--- /CKEditor/trunk/CHANGES.html	(revision 3946)
+++ /CKEditor/trunk/CHANGES.html	(revision 3947)
@@ -163,4 +163,5 @@
 		<li><a href="http://dev.fckeditor.net/ticket/3989">#3989</a> : Host page horizontal scrolling a lot when on having righ-to-left direction.</li>
 		<li><a href="http://dev.fckeditor.net/ticket/4001">#4001</a> : Create link around existing image result incorrect.</li>
+		<li><a href="http://dev.fckeditor.net/ticket/3956">#3956</a> : [IE]Fixed About dialog throw error in source mode regression.</li>
 	</ul>
 	<h3>
Index: /CKEditor/trunk/_source/plugins/dialog/plugin.js
===================================================================
--- /CKEditor/trunk/_source/plugins/dialog/plugin.js	(revision 3946)
+++ /CKEditor/trunk/_source/plugins/dialog/plugin.js	(revision 3947)
@@ -359,5 +359,5 @@
 					 * then IE would still leave the caret inside the editing area.
 					 */
-					if ( CKEDITOR.env.ie )
+					if ( this._.editor.mode == 'wysiwyg' && CKEDITOR.env.ie )
 					{
 						var $selection = editor.document.$.selection,
@@ -752,5 +752,5 @@
 				editor.focus();
 
-				if ( CKEDITOR.env.ie )
+				if ( editor.mode == 'wysiwyg' && CKEDITOR.env.ie )
 					editor.getSelection().unlock( true );
 			}