Removing last Painted point

[ebsaith]

Good Day

I store points in an array (points taken from position of mouse click)

In my paintEvent I draw points from array

painter.setPen(myPen);
            foreach(tempMark, myPoints)
            {
               painter.drawEllipse(tempMark, 2, 2);
            }

painter.setPen(myPen);
            foreach(tempMark, myPoints)
            {
               painter.drawEllipse(tempMark, 2, 2);
            }

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I created an UNDO Button that deletes the last point from array
I tested it, by writing points to file, That point is deleted

But my paintEvent still displays that point while I'm creating new points
(note all points must be displayed at all times during the run of the program)
If I click Undo, it should Remove only the last point
(which it does from the array - Button is working) But the point is still displayed on the screen

PushButton_Undo

myPoints.removeLast();
        this->repaint(); //-> probably this->repaint() not working! maybe

myPoints.removeLast();
        this->repaint(); //-> probably this->repaint() not working! maybe

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Do I add something to the paint Event?
Any Ideas?

Many Thanks