Index: _source/plugins/htmldataprocessor/plugin.js
===================================================================
--- _source/plugins/htmldataprocessor/plugin.js	(revision 6241)
+++ _source/plugins/htmldataprocessor/plugin.js	(revision )
@@ -122,8 +122,8 @@
 				// Attributes saved for changes and protected attributes.
 				[ ( /^data-cke-(saved|pa)-/ ), '' ],
 
-				// All "data-cke" attributes are to be ignored.
-				[ ( /^data-cke.*/ ), '' ],
+				// "data-cke" attributes are to be ignored.
+				[ ( /^data-cke-(?!nostyle).*/ ), '' ],
 
 				[ 'hidefocus', '' ]
 			],