diff --git a/python/message_wireshark_sink.py b/python/message_wireshark_sink.py
index 8eef849..70ca029 100644
--- a/python/message_wireshark_sink.py
+++ b/python/message_wireshark_sink.py
@@ -694,11 +694,11 @@ class message_wireshark_sink(gr.basic_block):
 
         self.message_port_register_in(pmt.intern("in"))
         self.set_msg_handler(pmt.intern("in"), self.msg_handler)
-		
-		# Register system_handler to stop execution when done.
-		self.message_port_register_in(pmt.intern("system"))
+
+        # Register system_handler to stop execution when done.
+        self.message_port_register_in(pmt.intern("system"))
         self.set_msg_handler(pmt.intern("system"), self.system_handler)
-		
+
         self.host = "127.0.0.1"
         self.port = 40868
         ###self.server = socket_pdu("UDP_SERVER", self.host, str(self.port))
@@ -710,11 +710,12 @@ class message_wireshark_sink(gr.basic_block):
 
     def system_handler(self, msg):
         #### Sends 'done' message, but does NOT end flowchart execution!
-		#### This is apparently a known bug in the Python connection to the message system.
-		####	Examples:
-		####		https://lists.gnu.org/archive/html/discuss-gnuradio/2015-03/msg00223.html
-		####		
-		#### A GNU Radio block written in C++ works as expected.
+        #### This is apparently a known bug in the Python connection to the message system.
+        ####    Examples:
+        ####        https://lists.gnu.org/archive/html/discuss-gnuradio/2015-03/msg00223.html
+        ####        https://lists.gnu.org/archive/html/discuss-gnuradio/2015-04/msg00093.html
+        ####        https://lists.gnu.org/archive/html/discuss-gnuradio/2016-07/msg00320.html
+        #### A GNU Radio block written in C++ works as expected.
         #### Workaround by raising exception...
         # print msg
         print ("End transmission. Press CTRL+C to continue...")