Index: /CKEditor/trunk/CHANGES.html
===================================================================
--- /CKEditor/trunk/CHANGES.html	(revision 6293)
+++ /CKEditor/trunk/CHANGES.html	(revision 6294)
@@ -73,4 +73,5 @@
 		<li><a href="http://dev.ckeditor.com/ticket/4208">#4208</a> : The <a href="http://docs.cksource.com/ckeditor_api/symbols/CKEDITOR.config.html#.disableObjectResizing">disableObjectResizing</a> setting now works on IE.</li>
 		<li><a href="http://dev.ckeditor.com/ticket/6242">#6242</a> : [IE] Editing existing links with href of a relative path mangles containing text.</li>
+		<li><a href="http://dev.ckeditor.com/ticket/5930">#5930</a> : [IE] Style definitions are no longer lowercased.</li>
 	</ul>
 	<h3>
Index: /CKEditor/trunk/_source/plugins/htmldataprocessor/plugin.js
===================================================================
--- /CKEditor/trunk/_source/plugins/htmldataprocessor/plugin.js	(revision 6293)
+++ /CKEditor/trunk/_source/plugins/htmldataprocessor/plugin.js	(revision 6294)
@@ -252,8 +252,11 @@
 	{
 		// IE outputs style attribute in capital letters. We should convert
-		// them back to lower case.
+		// them back to lower case, while not hurting the values (#5930)
 		defaultHtmlFilterRules.attributes.style = function( value, element )
 		{
-			return value.toLowerCase();
+			return value.replace( /(^|;)([^\:]+)/g, function( match )
+				{
+					return match.toLowerCase();
+				});
 		};
 	}