Index: modules/overlay/overlay-parent.js
===================================================================
RCS file: /cvs/drupal/drupal/modules/overlay/overlay-parent.js,v
retrieving revision 1.13
diff -u -r1.13 overlay-parent.js
--- modules/overlay/overlay-parent.js	6 Jan 2010 15:23:32 -0000	1.13
+++ modules/overlay/overlay-parent.js	6 Jan 2010 16:00:12 -0000
@@ -277,6 +277,9 @@
   self.$iframeDocument = null;
   self.$iframeBody = null;
 
+  // Reset lastHeight so the overlay fits user's viewport and the loading 
+  // spinner is centered.
+  self.lastHeight = 0;
   // No need to resize when loading.
   clearTimeout(self.resizeTimeoutID);