fix focus

openlp/core/ui/slidecontroller.py

@@ -851,6 +851,7 @@ class SlideController(DisplayController, RegistryProperties):
         if service_item.is_media():
             self.on_media_start(service_item)
         self.slide_selected(True)
+        self.preview_widget.setFocus()
         if old_item:
             # Close the old item after the new one is opened
             # This avoids the service theme/desktop flashing on screen