Index: lams_tool_spreadsheet/web/includes/javascript/rsrcspreadsheetitem.js
===================================================================
diff -u -r7f9f772433a7fd55c4475241d4e3bc0765f474e8 -r29fac4bd0bdf28bcaaeee7aae4020ccb15b6e520
--- lams_tool_spreadsheet/web/includes/javascript/rsrcspreadsheetitem.js	(.../rsrcspreadsheetitem.js)	(revision 7f9f772433a7fd55c4475241d4e3bc0765f474e8)
+++ lams_tool_spreadsheet/web/includes/javascript/rsrcspreadsheetitem.js	(.../rsrcspreadsheetitem.js)	(revision 29fac4bd0bdf28bcaaeee7aae4020ccb15b6e520)
@@ -110,5 +110,8 @@
 		// then refresh "basic tab" spreadsheetlist and close this window.
 	}
 	function cancelSpreadsheetItem(){
-		window.top.hideMessage();
-	}
+		var win = window.hideMessage ? window : window.top;
+		if (win.hideMessage != null){
+			win.hideMessage();
+		}
+	}
\ No newline at end of file