diff --git a/openlp/core/ui/servicemanager.py b/openlp/core/ui/servicemanager.py
index f49ce3e9a..aef334980 100644
--- a/openlp/core/ui/servicemanager.py
+++ b/openlp/core/ui/servicemanager.py
@@ -886,11 +886,12 @@ class ServiceManager(QtWidgets.QWidget, RegistryBase, Ui_ServiceManager, LogMixi
             if 'openlp_core' in item:
                 item = item['openlp_core']
                 self._save_lite = item.get('lite-service', False)
-                theme = item.get('service-theme', None)
-                if theme:
+                if theme := item.get('service-theme', None):
                     find_and_set_in_combo_box(self.theme_combo_box, theme, set_missing=False)
                     if theme == self.theme_combo_box.currentText():
                         self.service_theme = theme
+                        self.settings.setValue('servicemanager/service theme', theme)
+                        Registry().execute('theme_change_service')
             else:
                 if self._save_lite:
                     service_item.set_from_service(item, version=self.servicefile_version)
@@ -1480,8 +1481,8 @@ class ServiceManager(QtWidgets.QWidget, RegistryBase, Ui_ServiceManager, LogMixi
 
         :param current_index: The combo box index for the selected item
         """
-        new_service_theme = self.theme_combo_box.currentText()
-        self.settings.setValue('servicemanager/service theme', new_service_theme)
+        self.service_theme = self.theme_combo_box.currentText()
+        self.settings.setValue('servicemanager/service theme', self.service_theme)
         Registry().execute('theme_change_service')
 
     def on_theme_level_changed(self):
diff --git a/tests/openlp_core/ui/test_servicemanager.py b/tests/openlp_core/ui/test_servicemanager.py
index a0a111039..6d1a617ab 100644
--- a/tests/openlp_core/ui/test_servicemanager.py
+++ b/tests/openlp_core/ui/test_servicemanager.py
@@ -2546,3 +2546,63 @@ def test_process_service_items(mocked_fns_combo: Mock, MockServiceItem: Mock, se
         call({}, service_manager.service_path, service_manager.servicefile_version),
         call({}, version=service_manager.servicefile_version)
     ]
+
+
+def test_on_theme_combo_box_selected(service_manager: ServiceManager, registry: Registry, settings: Settings):
+    """Test the on_theme_combo_box_selected() method"""
+    # GIVEN: A ServiceManager
+    # Need this to get around globals/locals
+    results = {}
+
+    def theme_changed():
+        results['theme_changed'] = True
+
+    if registry.has_function('theme_change_service'):
+        registry.remove_function('theme_change_service')
+    registry.register_function('theme_change_service', theme_changed)
+    service_manager.theme_combo_box = MagicMock(**{'currentText.return_value': 'Blue'})
+
+    # WHEN: on_theme_combo_box_selected() is called
+    service_manager.on_theme_combo_box_selected(0)
+
+    # THEN: The correct calls should have been made
+    assert service_manager.service_theme == 'Blue'
+    assert results.get('theme_changed') is True
+    assert settings.value('servicemanager/service theme') == 'Blue'
+
+
+@patch('openlp.core.ui.servicemanager.find_and_set_in_combo_box')
+def test_on_service_theme_change(mocked_find: MagicMock, service_manager: ServiceManager, registry: Registry,
+                                 settings: Settings):
+    """Test the on_service_theme_change() method"""
+    # GIVEN: A ServiceManager
+    # Need this to get around globals/locals
+    results = {}
+
+    def theme_changed():
+        results['theme_changed'] = True
+
+    if registry.has_function('theme_change_service'):
+        registry.remove_function('theme_change_service')
+    registry.register_function('theme_change_service', theme_changed)
+    settings.setValue('servicemanager/service theme', 'Red')
+
+    # WHEN: on_service_theme_change() is called
+    service_manager.on_service_theme_change()
+
+    # THEN: The correct calls should have been made
+    assert service_manager.service_theme == 'Red'
+    assert results.get('theme_changed') is True
+    mocked_find.assert_called_once_with(service_manager.theme_combo_box, 'Red')
+
+
+def test_regenerate_changed_service_items(service_manager: ServiceManager):
+    """Test the regenerate_changed_service_items() method"""
+    # GIVEN: A ServiceManager, with a patched regenerate_service_items()
+    service_manager.regenerate_service_items = MagicMock()
+
+    # WHEN: regenerate_changed_service_items() is called
+    service_manager.regenerate_changed_service_items()
+
+    # THEN: regenerate_service_items() should have been called with the changed parameter
+    service_manager.regenerate_service_items.assert_called_once_with(changed=True)