Index: /CKEditor/trunk/_source/plugins/wysiwygarea/plugin.js
===================================================================
--- /CKEditor/trunk/_source/plugins/wysiwygarea/plugin.js	(revision 5288)
+++ /CKEditor/trunk/_source/plugins/wysiwygarea/plugin.js	(revision 5289)
@@ -255,5 +255,5 @@
 				paddingBlock.appendBogus();
 		}
-		
+
 		range.select();
 		editor.selectionChange();
@@ -678,4 +678,7 @@
 
 								CKEDITOR._[ 'contentDomReady' + editor.name ] = contentDomReady;
+
+								// The iframe is recreated on each call of setData, so we need to clear DOM objects
+								this.onDispose();
 								createIFrame( data );
 							},
@@ -715,6 +718,9 @@
 							},
 
-							unload : function( holderElement )
-							{
+							onDispose : function()
+							{
+								if ( !editor.document )
+									return;
+
 								editor.document.getDocumentElement().clearCustomData();
 								editor.document.getBody().clearCustomData();
@@ -722,4 +728,11 @@
 								editor.window.clearCustomData();
 								editor.document.clearCustomData();
+
+								iframe.clearCustomData();
+							},
+
+							unload : function( holderElement )
+							{
+								this.onDispose();
 
 								editor.window = editor.document = iframe = mainElement = isPendingFocus = null;