title: QTableView data disapears by opening another QTableView
body: <p>I have an application developed in Python using PyQt4, In which i used QTableView to display a reports.
  when i open one report window with QTableView it shows the result properly.
  If i open another report window with QTableView it shows the result properly.</p>
  
  <p>Now both the windows are displaying the data in there QTableViews.</p>
  
  <p>Now the issue is, When i select the 1st report window the data in it is disappearing.</p>
  
  <p>Can anyone tell me exactly whats wrong i am doing.</p>