Icon in system tray looks ugly if ARGB is used

#include <QtGui>
#include <X11/extensions/Xrender.h>

int main( int argc, char * argv[] )
{
    Colormap colormap = 0;
    Visual * visual = 0;
    int eventBase, errorBase;
    Display * dpy = XOpenDisplay( 0 );
    int screen = DefaultScreen( dpy );

    if ( XRenderQueryExtension( dpy, & eventBase, & errorBase) )
    {
        int nvi;
        XVisualInfo templ;
        templ.screen  = screen;
        templ.depth   = 32; // CHANGE TO 16 OR 24 IN ORDER TO WORK WELL
        templ.c_class = TrueColor;
        XVisualInfo * xvi
            = XGetVisualInfo( dpy, VisualScreenMask | VisualDepthMask
                                   | VisualClassMask, & templ, & nvi );

      for ( int i = 0; i < nvi; ++i )
      {
          XRenderPictFormat * format
              = XRenderFindVisualFormat( dpy, xvi[i].visual );
          if ( format->type == PictTypeDirect && format->direct.alphaMask )
          {
              visual = xvi[i].visual;
              colormap = XCreateColormap( dpy, RootWindow( dpy, screen ),
                                          visual, AllocNone);
              break;
          }
      }
    }

    QApplication app( dpy, argc, argv,
                      Qt::HANDLE( visual ), Qt::HANDLE( colormap ) );
    QSystemTrayIcon tray;
    tray.setIcon( QPixmap( "someicon.png") );
    tray.show();
    return app.exec();
}