Index: lams_tool_chat/web/pages/learning/chat_app.js
===================================================================
diff -u -r4d1146e33ddcaae15e13756729802dd5008aad00 -r1255c03efb8919e428d58f9b6b5529137428fab4
--- lams_tool_chat/web/pages/learning/chat_app.js	(.../chat_app.js)	(revision 4d1146e33ddcaae15e13756729802dd5008aad00)
+++ lams_tool_chat/web/pages/learning/chat_app.js	(.../chat_app.js)	(revision 1255c03efb8919e428d58f9b6b5529137428fab4)
@@ -275,6 +275,9 @@
 	}
 }
 function sendMsg(aForm) {
+	if (aForm.msg.value == "") {
+		return false;  // do not send empty messages.
+	}
 	var aMsg = new JSJaCMessage();
 	var rosterList = document.getElementById("roster_user_selector");
 	var selectedIndex = rosterList.selectedIndex;