diff --git a/gui/QT/option/settings.cpp b/gui/QT/option/settings.cpp
index 7f5c4eb0f..ff7d0d446 100644
--- a/gui/QT/option/settings.cpp
+++ b/gui/QT/option/settings.cpp
@@ -297,6 +297,7 @@ std::string Settings::getLaunchParams() const{
 
 	if(getOption("preview").isEnabled()){
 		out += "--capture-filter preview";
+		out += ":key=" + getSessRndKey();
 	}
 
 	out += getOption("video.source").getLaunchOption();
@@ -307,6 +308,7 @@ std::string Settings::getLaunchParams() const{
 			out += dispOpt.getParam();
 			out += "multiplier:" + dispOpt.getValue() + dispOpt.getSubVals();
 			out += "#preview";
+			out += ":key=" + getSessRndKey();
 		} else {
 			out += getOption("video.display").getLaunchOption();
 		}
@@ -314,6 +316,7 @@ std::string Settings::getLaunchParams() const{
 		if(getOption("preview").isEnabled()){
 			out += dispOpt.getParam();
 			out += "preview";
+			out += ":key=" + getSessRndKey();
 		}
 	}
 
@@ -338,9 +341,12 @@ std::string Settings::getLaunchParams() const{
 std::string Settings::getPreviewParams() const{
 	std::string out;
 
-	out += " --capture-filter preview,every:0";
+	out += " --capture-filter preview";
+	out += ":key=" + getSessRndKey();
+	out += ",every:0";
 	out += getOption("video.source").getLaunchOption();
 	out += " -d preview";
+	out += ":key=" + getSessRndKey();
 	out += getOption("audio.source").getLaunchOption();
 	out += getOption("audio.source.channels").getLaunchOption();
 	out += " -r dummy";
diff --git a/gui/QT/window/ultragrid_window.cpp b/gui/QT/window/ultragrid_window.cpp
index 9703237d1..59626a857 100644
--- a/gui/QT/window/ultragrid_window.cpp
+++ b/gui/QT/window/ultragrid_window.cpp
@@ -75,9 +75,9 @@ void UltragridWindow::initializeUgOpts(){
 
 	setArgs();
 
-	ui.displayPreview->setKey("ug_preview_disp_unix");
+	ui.displayPreview->setKey("ug_preview_disp_unix" + settings.getSessRndKey());
 	ui.displayPreview->start();
-	ui.capturePreview->setKey("ug_preview_cap_unix");
+	ui.capturePreview->setKey("ug_preview_cap_unix" + settings.getSessRndKey());
 	ui.capturePreview->start();
 
 	QStringList args = QCoreApplication::arguments();