diff --git a/openhantek/ChangeLog b/openhantek/ChangeLog
index 0e1615c..9df95fa 100644
--- a/openhantek/ChangeLog
+++ b/openhantek/ChangeLog
@@ -199,3 +199,7 @@
 
 2012-11-27 Oliver Haag  <oliver.haag@gmail.com>
 * Bugfix: Hantek::Control::setChannelUsed used setTrigger instead of setChannels
+
+2012-12-04 Oliver Haag  <oliver.haag@gmail.com>
+* Workaround for stacked QGLWidget on Mac OS X
+* Bugfix: Check for connected scope on setSamplerate/setRecordTime
diff --git a/openhantek/src/dsowidget.cpp b/openhantek/src/dsowidget.cpp
index 7552bb9..35d54d7 100644
--- a/openhantek/src/dsowidget.cpp
+++ b/openhantek/src/dsowidget.cpp
@@ -64,6 +64,12 @@ DsoWidget::DsoWidget(DsoSettings *settings, DataAnalyzer *dataAnalyzer, QWidget 
 	this->zoomScope->setGenerator(this->generator);
 	this->zoomScope->setZoomMode(true);
 	
+#ifdef OS_DARWIN
+	// Workaround for https://bugreports.qt-project.org/browse/QTBUG-8580
+	this->mainScope->hide();
+	this->mainScope->show();
+#endif
+	
 	// The offset sliders for all possible channels
 	this->offsetSlider = new LevelSlider(Qt::RightArrow);
 	for(int channel = 0; channel < this->settings->scope.voltage.count(); ++channel) {
diff --git a/openhantek/src/hantek/control.cpp b/openhantek/src/hantek/control.cpp
index 2c17c7c..32576c6 100644
--- a/openhantek/src/hantek/control.cpp
+++ b/openhantek/src/hantek/control.cpp
@@ -1040,6 +1040,9 @@ namespace Hantek {
 	/// \param samplerate The samplerate that should be met (S/s), 0.0 to restore current samplerate.
 	/// \return The samplerate that has been set, 0.0 on error.
 	double Control::setSamplerate(double samplerate) {
+		if(!this->device->isConnected())
+			return 0.0;
+		
 		if(samplerate == 0.0) {
 			samplerate = this->settings.samplerate.target.samplerate;
 		}
@@ -1067,6 +1070,9 @@ namespace Hantek {
 	/// \param duration The record time duration that should be met (s), 0.0 to restore current record time.
 	/// \return The record time duration that has been set, 0.0 on error.
 	double Control::setRecordTime(double duration) {
+		if(!this->device->isConnected())
+			return 0.0;
+		
 		if(duration == 0.0) {
 			duration = this->settings.samplerate.target.duration;
 		}