Index: dialin/ui/hd_simulator.py
===================================================================
diff -u -r9691b4ccfd3732233addfb5820eb03d41c917bab -ra45233b3e9562bb2b8ee19cd572f2d8d2f06bb5d
--- dialin/ui/hd_simulator.py	(.../hd_simulator.py)	(revision 9691b4ccfd3732233addfb5820eb03d41c917bab)
+++ dialin/ui/hd_simulator.py	(.../hd_simulator.py)	(revision a45233b3e9562bb2b8ee19cd572f2d8d2f06bb5d)
@@ -188,6 +188,16 @@
         @param message: the confirm treatment message
         @return: None
         """
+        START_POS = DenaliMessage.PAYLOAD_START_INDEX
+        END_POS = START_POS + 4
+
+        request = struct.unpack('i', bytearray(
+            message['message'][START_POS:END_POS]))[0]
+
+        if request == 0:
+            self.logger.debug("Received UI cancel confirmation of Treatment Parameters. ")
+            return
+
         self.logger.debug("Received UI confirmation of Treatment Parameters. ")
 
         state = 0