private void setScopeFields() {
		if (xminField == null) {
			xminField = new RealNumberTextField(xAxis.minimum, -Double.MAX_VALUE, Double.MAX_VALUE);
		}
		else {
			xminField.setValue(xAxis.minimum);
			ActionListener[] al = xminField.getActionListeners();
			for (ActionListener a : al)
				xminField.removeActionListener(a);
		}
		if (xmaxField == null) {
			xmaxField = new RealNumberTextField(xAxis.maximum, -Double.MAX_VALUE, Double.MAX_VALUE);
		}
		else {
			xmaxField.setValue(xAxis.maximum);
			ActionListener[] al = xmaxField.getActionListeners();
			for (ActionListener a : al)
				xmaxField.removeActionListener(a);
		}
		if (yminField == null) {
			yminField = new RealNumberTextField(yAxis.minimum, -Double.MAX_VALUE, Double.MAX_VALUE);
		}
		else {
			yminField.setValue(yAxis.minimum);
			ActionListener[] al = yminField.getActionListeners();
			for (ActionListener a : al)
				yminField.removeActionListener(a);
		}
		if (ymaxField == null) {
			ymaxField = new RealNumberTextField(yAxis.maximum, -Double.MAX_VALUE, Double.MAX_VALUE);
		}
		else {
			ymaxField.setValue(yAxis.maximum);
			ActionListener[] al = ymaxField.getActionListeners();
			for (ActionListener a : al)
				ymaxField.removeActionListener(a);
		}
	}