Zooming in but not out

[nitriles]

I have i graph in which i can succesfully zoom (left mouse button) but when i want to zoom out (right mouse button) i get a whole new graph plot and my previous graph is gone. Like it replots a graph on top of it.
This is my code:

class GraphPlot(Qwt.QwtPlot):
 
    def __init__(self, *args):
        Qwt.QwtPlot.__init__(self, *args)
        #self.plot = Qwt.QwtPlot(self)
 
	# make a QwtPlot widget
	self.setTitle("Graph Plot")
        #self.__initTracking()
        self.__initZooming()
...
...
    def __initZooming(self):
        self.replot()
        self.zoomer = Qwt.QwtPlotZoomer(Qwt.QwtPlot.xBottom,
                                        Qwt.QwtPlot.yLeft,
                                        Qwt.QwtPicker.DragSelection,
                                        Qwt.QwtPicker.AlwaysOff,
                                        self.canvas())
        self.zoomer.setRubberBandPen(qt.QPen(qt.Qt.black))
        self.replot()
 
    #end __initZooming

class GraphPlot(Qwt.QwtPlot):

    def __init__(self, *args):
        Qwt.QwtPlot.__init__(self, *args)
        #self.plot = Qwt.QwtPlot(self)

	# make a QwtPlot widget
	self.setTitle("Graph Plot")
        #self.__initTracking()
        self.__initZooming()
...
...
    def __initZooming(self):
        self.replot()
        self.zoomer = Qwt.QwtPlotZoomer(Qwt.QwtPlot.xBottom,
                                        Qwt.QwtPlot.yLeft,
                                        Qwt.QwtPicker.DragSelection,
                                        Qwt.QwtPicker.AlwaysOff,
                                        self.canvas())
        self.zoomer.setRubberBandPen(qt.QPen(qt.Qt.black))
        self.replot()

    #end __initZooming

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thanks a lot!

[nitriles]

Wohoo i fixed it, never mind!
dont place it in the class, place it here:

def main(args):
    app = qt.QApplication(args)
    demo = make()
    app.setMainWidget(demo)
 
    zoomer = Qwt.QwtPlotZoomer(Qwt.QwtPlot.xBottom,
                               Qwt.QwtPlot.yLeft,
                               Qwt.QwtPicker.DragSelection,
                               Qwt.QwtPicker.AlwaysOff,
                               demo.canvas())
    zoomer.setRubberBandPen(qt.QPen(qt.Qt.green))
    picker = Qwt.QwtPlotPicker(Qwt.QwtPlot.xBottom,
                               Qwt.QwtPlot.yLeft,
                               Qwt.QwtPicker.NoSelection,
                               Qwt.QwtPlotPicker.CrossRubberBand,
                               Qwt.QwtPicker.AlwaysOn,
                               demo.canvas())
    picker.setTrackerPen(qt.QPen(qt.Qt.red))
 
    sys.exit(app.exec_loop())
 
# main()

def main(args):
    app = qt.QApplication(args)
    demo = make()
    app.setMainWidget(demo)

    zoomer = Qwt.QwtPlotZoomer(Qwt.QwtPlot.xBottom,
                               Qwt.QwtPlot.yLeft,
                               Qwt.QwtPicker.DragSelection,
                               Qwt.QwtPicker.AlwaysOff,
                               demo.canvas())
    zoomer.setRubberBandPen(qt.QPen(qt.Qt.green))
    picker = Qwt.QwtPlotPicker(Qwt.QwtPlot.xBottom,
                               Qwt.QwtPlot.yLeft,
                               Qwt.QwtPicker.NoSelection,
                               Qwt.QwtPlotPicker.CrossRubberBand,
                               Qwt.QwtPicker.AlwaysOn,
                               demo.canvas())
    picker.setTrackerPen(qt.QPen(qt.Qt.red))
    
    sys.exit(app.exec_loop())

# main()

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