diff --git a/main.py b/main.py
index 101ea3d..fc7f737 100644
--- a/main.py
+++ b/main.py
@@ -22,8 +22,6 @@ class MainWindow(QMainWindow):
 
         self.updateThread = QThread()
 
-        print(QThread.currentThread(),self.updateThread)
-
         self.mainLoop = mainLoop(self)
 
         self.mainLoop.moveToThread(self.updateThread)
@@ -66,12 +64,17 @@ class MainWindow(QMainWindow):
 
     def updateFPS(self):
         widget = self.findChild(QLabel,"mainFps")
-        widget.setText(f"fps : {1000/self.fpsTimer.restart():.1f}")
+        t = self.fpsTimer.restart()
+        if(t == 0):
+            return
+        widget.setText(f"fps : {1000/t:.1f}")
         widget.update()
 
     @Slot(int)
     def updatePhysicsFps(self,t):
         widget = self.findChild(QLabel,"physicsFPS")
+        if(t == 0):
+            return
         widget.setText(f"ph fps : {1000/t:.1f}")
 
     def openNetwork(self):
@@ -82,6 +85,12 @@ class MainWindow(QMainWindow):
         filename = QFileDialog.getOpenFileName(self,"Open Vehicle trip description", "./", "Route File (*.rou.xml)")
         self.mainLoop.openVehicles(filename[0])
 
+    def close(self):
+        self.updateThread.quit()
+        self.updateThread.wait()
+        super().close()
+
+
 
 if __name__ == "__main__":
     app = QApplication()