Index: library/pyjamas/platform/DOMMozilla.py
===================================================================
--- library/pyjamas/platform/DOMMozilla.py	(revision 551)
+++ library/pyjamas/platform/DOMMozilla.py	(working copy)
@@ -61,8 +61,10 @@
         }
         parent = parent.parentNode;
     }
-
-    return left + $doc.body.scrollLeft + $doc.documentElement.scrollLeft;
+    # getBoundingClientRect can be float: 73.1 instead of 74, see
+    # gwt's workaround at user/src/com/google/gwt/dom/client/DOMImplMozilla.java:47
+    # Please note, their implementation has 1px offset.
+    return Math.ceil(left + $doc.body.scrollLeft + $doc.documentElement.scrollLeft);
     """)
 
 # This is what is in GWT 1.5 for getAbsoluteTop.  err...
@@ -103,7 +105,7 @@
         parent = parent.parentNode;
     }
 
-    return top + $doc.body.scrollTop + $doc.documentElement.scrollTop;
+    return Math.ceil(top + $doc.body.scrollTop + $doc.documentElement.scrollTop);
     """)
 
 def getChildIndex(parent, child):