Fix a problem in the settings which prevented the plugins from showing up in the library

openlp/core/common/settings.py

@@ -586,6 +586,8 @@ class Settings(QtCore.QSettings):
             # Sometimes setting is string instead of a boolean.
             return setting == 'true'
         if isinstance(default_value, int):
+            if setting is None:
+                return 0
             return int(setting)
         return setting
 

openlp/core/ui/mainwindow.py

@@ -1075,7 +1075,7 @@ class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow, LogMixin, RegistryPropert
         # Close down the display
         if self.live_controller.display:
             self.live_controller.display.close()
-            self.live_controller.display = None
+            # self.live_controller.display = None
         # Clean temporary files used by services
         self.service_manager_contents.clean_up()
         if is_win():