Index: thickbox.js
===================================================================
--- thickbox.js	(revision 13805)
+++ thickbox.js	(working copy)
@@ -479,6 +479,11 @@
 }
 
 TB.remove = function ($e, $on_close) {
+	if (TB.useStack && TB.windows.length == 0) {
+		// no windows opened, but TB.remove called -> ignore
+		return ;
+	}
+
 	var $last_window = TB.useStack && TB.windows.length <= 1;
 
 	$('#TB_imageOff').unbind('click');