diff --git a/scalezoomer.cpp b/scalezoomer.cpp
--- a/scalezoomer.cpp
+++ b/scalezoomer.cpp
@@ -28,10 +28,35 @@ ScaleZoomer::ScaleZoomer(QwtPlot* plot, 
 {
     _plot = plot;
     _zoomer = zoomer;
+    connect(&bottomPicker, &ScalePicker::pickStarted, this, &ScaleZoomer::bottomPickStarted);
+    connect(&bottomPicker, &ScalePicker::picking, this, &ScaleZoomer::bottomPicking);
     connect(&bottomPicker, &ScalePicker::picked, this, &ScaleZoomer::bottomPicked);
     connect(&leftPicker, &ScalePicker::picked, this, &ScaleZoomer::leftPicked);
 }
 
+void ScaleZoomer::bottomPickStarted(double firstPos)
+{
+    double yMin = _plot->axisScaleDiv(QwtPlot::yLeft).lowerBound();
+    double yMax = _plot->axisScaleDiv(QwtPlot::yLeft).upperBound();
+    rectShape.setRect(QRectF(firstPos, yMin, 2, yMax-yMin));
+    rectShape.attach(_plot);
+    _plot->replot();
+}
+
+void ScaleZoomer::bottomPicking(double firstPos, double lastPos)
+{
+    double yMin = _plot->axisScaleDiv(QwtPlot::yLeft).lowerBound();
+    double yMax = _plot->axisScaleDiv(QwtPlot::yLeft).upperBound();
+    if (lastPos > firstPos) {
+        rectShape.setRect(QRectF(firstPos, yMin, lastPos-firstPos, yMax-yMin));
+    }
+    else
+    {
+        rectShape.setRect(QRectF(lastPos, yMin, firstPos-lastPos, yMax-yMin));
+    }
+    _plot->replot();
+}
+
 void ScaleZoomer::bottomPicked(double firstPos, double lastPos)
 {
     QRectF zRect;
@@ -49,6 +74,8 @@ void ScaleZoomer::bottomPicked(double fi
     zRect.setBottom(_plot->axisScaleDiv(QwtPlot::yLeft).lowerBound());
     zRect.setTop(_plot->axisScaleDiv(QwtPlot::yLeft).upperBound());
     _zoomer->zoom(zRect);
+    rectShape.detach();
+    _plot->replot();
 }
 
 void ScaleZoomer::leftPicked(double firstPos, double lastPos)