title: how to use Qt setWindowFilePath
body: <p>I can't seem to get setWindowFilePath to work in any of my projects.  The value is stored and can be retrieved, but it never shows up in the title bar of my app.  It does work correctly in a sample app I downloaded, but I can't find what they do differently.  Anyway, here's a simple app I created to demonstrate the problem.  I pasted the code from the 3 files, mainwin.h, main.cpp, and mainwin.cpp below.</p>
  
  <p>Any ideas?  I'm using Qt 4.6.3 on Windows 7, with the MS compiler.</p>
  
  <pre><code>#ifndef MAINWIN_H
  #define MAINWIN_H
  
  #include &lt;QMainWindow&gt;
  
  class mainwin : public QMainWindow
  {
      Q_OBJECT
  public:
      explicit mainwin(QWidget *parent = 0);
  
  signals:
  
  public slots:
  
  };
  
  #endif // MAINWIN_H
  
  #include "mainwin.h"
  #include &lt;QApplication&gt;
  
  int main(int argc, char *argv[])
  {
      QApplication app(argc, argv);
      app.setApplicationName("my test");
      app.setOrganizationName("NTFMO");
      mainwin window;
      window.show();
      return app.exec();
  }
  
  #include "mainwin.h"
  
  mainwin::mainwin(QWidget *parent) :
      QMainWindow(parent)
  {
    setWindowFilePath("C:\asdf.txt");
  
  }
  </code></pre>