diff --git a/mainwindow.cpp b/mainwindow.cpp
index 08c1140..3d185d0 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -41,6 +41,7 @@ MainWindow::MainWindow()
     connect(dock->timeScaleCheckBox, SIGNAL(stateChanged(int)), &spectrogram, SLOT(setTimeScaleEnable(int)));
     connect(&spectrogram, SIGNAL(cursorFrequencyChanged(QString)), dock->cursorFrequencyLabel, SLOT(setText(QString)));
     connect(&spectrogram, SIGNAL(cursorTimeChanged(QString)), dock->cursorTimeLabel, SLOT(setText(QString)));
+    connect(dock->deltaDragCheckBox, SIGNAL(stateChanged(int)), &spectrogram, SLOT(setDeltaDragEnable(int)));
     connect(&spectrogram, SIGNAL(deltaFrequencyChanged(QString)), dock->deltaFrequencyLabel, SLOT(setText(QString)));
     connect(&spectrogram, SIGNAL(deltaTimeChanged(QString)), dock->deltaTimeLabel, SLOT(setText(QString)));
 }
diff --git a/spectrogram.cpp b/spectrogram.cpp
index b92ea43..195522d 100644
--- a/spectrogram.cpp
+++ b/spectrogram.cpp
@@ -36,6 +36,7 @@ Spectrogram::Spectrogram()
 	powerMax = 0.0f;
 	powerMin = -50.0f;
 	timeScaleIsEnabled = true;
+	deltaDragIsEnabled = true;
 
 	for (int i = 0; i < 256; i++) {
 		float p = (float)i / 256;
@@ -81,8 +82,10 @@ void Spectrogram::xyToFreqTime(int x, int y, float *freq, float *time) {
 }
 
 void Spectrogram::mouseReleaseEvent(QMouseEvent *event) {
-	cursorStartX = -1;
-	update();
+	if (deltaDragIsEnabled) {
+		cursorStartX = -1;
+		update();
+	}
 }
 
 void Spectrogram::mouseMoveEvent(QMouseEvent *event) {
@@ -102,8 +105,12 @@ void Spectrogram::mouseMoveEvent(QMouseEvent *event) {
 }
 
 void Spectrogram::mousePressEvent(QMouseEvent *event) {
-	cursorEndX = cursorStartX = event->x();
-	cursorEndY = cursorStartY = event->y();
+	if (cursorStartX == -1) {
+		cursorEndX = cursorStartX = event->x();
+		cursorEndY = cursorStartY = event->y();
+	} else {
+		cursorStartX = -1;
+	}
 	update();
 }
 
@@ -282,6 +289,11 @@ void Spectrogram::setTimeScaleEnable(int state)
 	update();
 }
 
+void Spectrogram::setDeltaDragEnable(int state)
+{
+	deltaDragIsEnabled = (state == Qt::Checked);
+}
+
 
 int Spectrogram::getHeight()
 {
diff --git a/spectrogram.h b/spectrogram.h
index 1514347..d96b708 100644
--- a/spectrogram.h
+++ b/spectrogram.h
@@ -54,6 +54,7 @@ public slots:
 	void setPowerMin(int power);
 	void setZoomLevel(int zoom);
 	void setTimeScaleEnable(int state);
+	void setDeltaDragEnable(int state);
 
 protected:
 	void paintEvent(QPaintEvent *event);
@@ -80,6 +81,7 @@ private:
 	float powerMax;
 	float powerMin;
 	bool timeScaleIsEnabled;
+	bool deltaDragIsEnabled;
 	int cursorStartX = -1, cursorStartY;
 	int cursorEndX, cursorEndY;
 
diff --git a/spectrogramcontrols.cpp b/spectrogramcontrols.cpp
index 625b0fd..9f737b1 100644
--- a/spectrogramcontrols.cpp
+++ b/spectrogramcontrols.cpp
@@ -66,6 +66,10 @@ SpectrogramControls::SpectrogramControls(const QString & title, QWidget * parent
 	cursorTimeLabel = new QLabel();
 	layout->addRow(new QLabel(tr("Cursor time:")), cursorTimeLabel);
 
+	deltaDragCheckBox = new QCheckBox(widget);
+	deltaDragCheckBox->setCheckState(Qt::Checked);
+	layout->addRow(new QLabel(tr("Delta dragging:")), deltaDragCheckBox);
+
 	deltaFrequencyLabel = new QLabel();
 	layout->addRow(new QLabel(tr("Delta frequency:")), deltaFrequencyLabel);
 
diff --git a/spectrogramcontrols.h b/spectrogramcontrols.h
index 6a9a165..3f835aa 100644
--- a/spectrogramcontrols.h
+++ b/spectrogramcontrols.h
@@ -54,6 +54,7 @@ public:
 	QCheckBox *timeScaleCheckBox;
 	QLabel *cursorFrequencyLabel;
 	QLabel *cursorTimeLabel;
+	QCheckBox *deltaDragCheckBox;
 	QLabel *deltaFrequencyLabel;
 	QLabel *deltaTimeLabel;
 };