diff --git a/src/plugins/qmlprojectmanager/qmlprojectruncontrol.cpp b/src/plugins/qmlprojectmanager/qmlprojectruncontrol.cpp
index 7681f2c03f5a1f4b2579360b1b16bac6f17f72e4..ba664700374269015791d289ad3e3fc8b1d9a430 100644
--- a/src/plugins/qmlprojectmanager/qmlprojectruncontrol.cpp
+++ b/src/plugins/qmlprojectmanager/qmlprojectruncontrol.cpp
@@ -198,9 +198,8 @@ RunControl *QmlRunControlFactory::createDebugRunControl(QmlProjectRunConfigurati
     params.executable = runConfig->observerPath();
     params.qmlServerAddress = "127.0.0.1";
     params.qmlServerPort = runConfig->qmlDebugServerPort();
-    params.processArgs = runConfig->viewerArguments();
-    Utils::QtcProcess::addArg(&params.processArgs,
-            QLatin1String("-qmljsdebugger=port:") + QString::number(runConfig->qmlDebugServerPort()));
+    params.processArgs = QLatin1String("-qmljsdebugger=port:") + QString::number(runConfig->qmlDebugServerPort());
+    params.processArgs += QLatin1Char(' ') + runConfig->viewerArguments();
     params.workingDirectory = runConfig->workingDirectory();
     params.environment = runConfig->environment();
     params.displayName = runConfig->displayName();