try to fix ui freeze when filtering huge files

bigtext.py

@@ -42,15 +42,13 @@ class FileObserver(FileSystemEventHandler):
 
 class FileWatchdogThread(QRunnable):
 
-    observer = None
-
     def __init__(self, big_text, file: str):
         super(FileWatchdogThread, self).__init__()
         self.file = file
         self.big_text = big_text
+        self.observer = Observer()
 
     def run(self) -> None:
-        self.observer = Observer()
         self.observer.schedule(FileObserver(self.big_text), self.file)
         self.observer.start()
 
@@ -137,9 +135,9 @@ class InnerBigText(QWidget):
                 self.scroll_by_lines(-lines_to_scroll)
             if e.key() == Qt.Key.Key_PageDown:
                 self.scroll_by_lines(lines_to_scroll)
-            if e.key() == 16777235: # page up
+            if e.key() == 16777235:  # page up
                 self.scroll_by_lines(-3)
-            if e.key() == 16777237: # page down
+            if e.key() == 16777237:  # page down
                 self.scroll_by_lines(3)
         if e.modifiers() == Qt.KeyboardModifier.ControlModifier and e.key() == 67:  # ctrl + c
             self.copy_selection()
@@ -238,7 +236,7 @@ class InnerBigText(QWidget):
             cb.setText(selected_text)
 
     def paintEvent(self, event: QPaintEvent) -> None:
-        #print("paintEvent")
+        # print("paintEvent")
         painter = QPainter(self)
         painter.setFont(self.model.settings.font())
         painter.setPen(QColor(0, 0, 0))