Index: FCKeditor/trunk/editor/_source/internals/fcktools.js
===================================================================
--- FCKeditor/trunk/editor/_source/internals/fcktools.js	(revision 1091)
+++ FCKeditor/trunk/editor/_source/internals/fcktools.js	(revision 1092)
@@ -458,6 +458,12 @@
 		}
 	}
-	x += w.document.body.offsetLeft ;
-	y += w.document.body.offsetTop ;
+
+	// document.body is a special case when it comes to offsetTop and offsetLeft values.
+	// We can't just blindly sum it up in the while loop above.
+	if ( FCKDomTools.GetCurrentElementStyle( w, w.document.body, 'position') != 'static' )
+	{
+		x += w.document.body.offsetLeft ;
+		y += w.document.body.offsetTop ;
+	}
 	return { "x" : x, "y" : y } ;
 }