improve responsiveness when switching applications

gotify_tray/tasks.py

@@ -215,6 +215,7 @@ class ProcessMessageTask(BaseTask):
 
 class ProcessMessagesTask(BaseTask):
     message_processed = pyqtSignal(int, gotify.GotifyMessageModel)
+
     def __init__(self, page: gotify.GotifyPagedMessagesModel):
         super(ProcessMessagesTask, self).__init__()
         self.page = page
@@ -225,3 +226,6 @@ class ProcessMessagesTask(BaseTask):
             if image_url := get_image(message.message):
                 downloader.get_filename(image_url)
             self.message_processed.emit(i, message)
+
+            # Prevent locking up the UI when there are a lot of messages with images ready at the same time
+            time.sleep(0.001)