Index: _source/plugins/dialog/plugin.js
===================================================================
--- _source/plugins/dialog/plugin.js	(revision 4534)
+++ _source/plugins/dialog/plugin.js	Tue Nov 24 02:14:08 CST 2009
@@ -1673,11 +1673,13 @@
 
 		if ( !coverElement )
 		{
+			var backgroundColorStyle = editor.config.dialog_backgroundCoverColor || 'white';
+
 			var html = [
 					'<div style="position: ', ( CKEDITOR.env.ie6Compat ? 'absolute' : 'fixed' ),
 					'; z-index: ', editor.config.baseFloatZIndex,
 					'; top: 0px; left: 0px; ',
-					'background-color: ', editor.config.dialog_backgroundCoverColor || 'white',
+					( !CKEDITOR.env.ie6Compat ? 'background-color: ' + backgroundColorStyle : '' ),
 					'" id="cke_dialog_background_cover">'
 				];
 
@@ -1685,7 +1687,8 @@
 			if ( CKEDITOR.env.ie6Compat )
 			{
 				// Support for custom document.domain in IE.
-				var isCustomDomain = CKEDITOR.env.isCustomDomain();
+				var isCustomDomain = CKEDITOR.env.isCustomDomain(),
+					iframeHtml = '<html><body style=\\\'background-color:' + backgroundColorStyle + ';\\\'></body></html>';
 
 				html.push(
 					'<iframe' +
@@ -1694,15 +1697,12 @@
 						' id="cke_dialog_background_iframe"' +
 						' src="javascript:' );
 
-				html.push(
-						isCustomDomain ?
-							'void((function(){' +
+				html.push( 'void((function(){' +
 								'document.open();' +
-								'document.domain=\'' + document.domain + '\';' +
+								( isCustomDomain ? 'document.domain=\'' + document.domain + '\';' : '' ) +
+								'document.write( \'' + iframeHtml + '\' );' +
 								'document.close();' +
-							'})())'
-						:
-							'\'\'' );
+							'})())' );
 
 				html.push(
 						'"' +
