Index: /CKEditor/trunk/_source/plugins/undo/plugin.js
===================================================================
--- /CKEditor/trunk/_source/plugins/undo/plugin.js	(revision 5500)
+++ /CKEditor/trunk/_source/plugins/undo/plugin.js	(revision 5501)
@@ -149,10 +149,10 @@
 	{
 		this.editor = editor;
-		var contents	= editor.getSnapshot(),
+		var contents = editor.getSnapshot(),
 			selection	= contents && editor.getSelection();
 
 		// In IE, we need to remove the expando attributes.
 		CKEDITOR.env.ie && contents && ( contents = contents.replace( /\s+_cke_expando=".*?"/g, '' ) );
-		
+
 		this.contents	= contents;
 		this.bookmarks	= selection && selection.createBookmarks2( true );
@@ -166,12 +166,7 @@
 		equals : function( otherImage, contentOnly )
 		{
-			
+
 			var thisContents = this.contents,
-				otherContents = otherImage.contents,
-				// Registered filters makes Image to respond correct on service markup of SCAYT and any other plugins 
-				// The editor object is absent in context of Image by default, 
-				// so for prototyping we use hardcoded editor name "editor1"
-				thisEqualsFilters = CKEDITOR.instances.editor1._.imageEqualsFilters,
-				i,err;
+				otherContents = otherImage.contents;
 
 			// For IE6/7 : Comparing only the protected attribute values but not the original ones.(#4522)
@@ -181,16 +176,5 @@
 				otherContents = otherContents.replace( protectedAttrs, '' );
 			}
-			
-			
-			// Run custom filters
-			if (thisEqualsFilters && thisEqualsFilters.length)
-				for ( i in thisEqualsFilters )
-					try{
-						filteredContents = thisEqualsFilters[i].apply(null,[thisContents,otherContents]);
-						thisContents = filteredContents[0];
-						otherContents = filteredContents[1];
-					}catch (err){}
-			
-					
+
 			if ( thisContents != otherContents )
 				return false;