From af4715dc3c2a53c7f7a836c16377af7f894e0444 Mon Sep 17 00:00:00 2001
From: Tomas Groth <second@tgc.dk>
Date: Tue, 2 Dec 2014 09:46:19 +0000
Subject: [PATCH] Remove the registered functions instead of overwriting

---
 openlp/core/common/registry.py |  9 ++-------
 openlp/core/ui/maindisplay.py  | 17 ++++++++++++++---
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/openlp/core/common/registry.py b/openlp/core/common/registry.py
index 70c2fe3bd..455c3385d 100644
--- a/openlp/core/common/registry.py
+++ b/openlp/core/common/registry.py
@@ -105,7 +105,7 @@ class Registry(object):
         if key in self.service_list:
             del self.service_list[key]
 
-    def register_function(self, event, function, overwrite=False):
+    def register_function(self, event, function):
         """
         Register an event and associated function to be called
 
@@ -113,9 +113,8 @@ class Registry(object):
             will/may need to respond to a single action and the caller does not need to understand or know about the
             recipients.
         :param function: The function to be called when the event happens.
-        :param overwrite: There should only be one function with the registred name.
         """
-        if not overwrite and event in self.functions_list:
+        if event in self.functions_list:
             self.functions_list[event].append(function)
         else:
             self.functions_list[event] = [function]
@@ -127,10 +126,6 @@ class Registry(object):
         :param event: The function description..
         :param function: The function to be called when the event happens.
         """
-        if not self.running_under_test:
-            trace_error_handler(log)
-            log.error('Invalid Method call for key %s' % event)
-            raise KeyError('Invalid Method call for key %s' % event)
         if event in self.functions_list:
             self.functions_list[event].remove(function)
 
diff --git a/openlp/core/ui/maindisplay.py b/openlp/core/ui/maindisplay.py
index ceb94a2a9..d238a1f5e 100644
--- a/openlp/core/ui/maindisplay.py
+++ b/openlp/core/ui/maindisplay.py
@@ -153,9 +153,20 @@ class MainDisplay(OpenLPMixin, Display, RegistryProperties):
         self.setAttribute(QtCore.Qt.WA_DeleteOnClose)
         self.set_transparency(False)
         if self.is_live:
-            Registry().register_function('live_display_hide', self.hide_display, True)
-            Registry().register_function('live_display_show', self.show_display, True)
-            Registry().register_function('update_display_css', self.css_changed, True)
+            Registry().register_function('live_display_hide', self.hide_display)
+            Registry().register_function('live_display_show', self.show_display)
+            Registry().register_function('update_display_css', self.css_changed)
+
+    def close(self):
+        """
+        Remove registered function on close.
+        """
+        if self.is_live:
+            Registry().remove_function('live_display_hide', self.hide_display)
+            Registry().remove_function('live_display_show', self.show_display)
+            Registry().remove_function('update_display_css', self.css_changed)
+        super().close()
+
 
     def set_transparency(self, enabled):
         """