Hello Guys, I am trying to learn how to use the qtreactor (I am using pyQT and TwistedMatrix) but i am facing few issues. I created a simple Ui, just a MainWindow and a QTreeWidget. The point is: I can execute and See my MainWindow using the code below under Mac OS X, but if I execute the same code on Linux, it will show me only the window, without the QTreeWidget. I noticied that the issue is under the install() method, since I can see the Window correctly if I remove the install() method. Does anyone know if I am missing something? # -*- coding: utf-8 -*- """The user interface for our app""" import os,sys from qt4reactor import install; from PyQt4 import QtCore,QtGui from windowUi import Ui_MainWindow class Main(QtGui.QMainWindow): def __init__(self): QtGui.QMainWindow.__init__(self) self.ui=Ui_MainWindow() self.ui.setupUi(self) def main(): app = QtGui.QApplication(sys.argv) qt4reactor.install() window=Main() window.show() from twisted.internet import reactor reactor.run() sys.exit(app.exec_()) if __name__ == "__main__": main() Thanks Renan Mathias Fernandes