diff --git a/src/plugins/debugger/qml/qmlinspectoradapter.cpp b/src/plugins/debugger/qml/qmlinspectoradapter.cpp
index e48c3392b39664a466481dc2ce8cf0f05e91ec07..164d77258c33d78f4e24608f26c37e3dd9c73f11 100644
--- a/src/plugins/debugger/qml/qmlinspectoradapter.cpp
+++ b/src/plugins/debugger/qml/qmlinspectoradapter.cpp
@@ -251,7 +251,8 @@ void QmlInspectorAdapter::engineClientStatusChanged(QmlDebug::ClientStatus statu
     BaseEngineDebugClient *client
             = qobject_cast<BaseEngineDebugClient*>(sender());
 
-    if (status == QmlDebug::Enabled) {
+    if (status == QmlDebug::Enabled && !m_engineClientConnected) {
+        // We accept the first client that is enabled and reject the others.
         QTC_ASSERT(client, return);
         setActiveEngineClient(client);
     } else if (m_engineClientConnected && client == m_engineClient) {
diff --git a/src/plugins/qt4projectmanager/qmakestep.cpp b/src/plugins/qt4projectmanager/qmakestep.cpp
index 26e4eefb7cb113c00c373704814a1cd8ee8c8534..310759593e2b5ba32cfe6382b93ce204dcd9563a 100644
--- a/src/plugins/qt4projectmanager/qmakestep.cpp
+++ b/src/plugins/qt4projectmanager/qmakestep.cpp
@@ -201,9 +201,12 @@ QStringList QMakeStep::deducedArguments()
         if (!version->needsQmlDebuggingLibrary()) {
             // This Qt version has the QML debugging services built in, however
             // they still need to be enabled at compile time
-            arguments << (version->qtVersion().majorVersion >= 5 ?
-                          QLatin1String(Constants::QMAKEVAR_DECLARATIVE_DEBUG5) :
-                          QLatin1String(Constants::QMAKEVAR_DECLARATIVE_DEBUG4));
+            // TODO: For Qt5, we can pass both arguments as there can be Qt Quick 1/2 projects.
+            // Currently there is no support for debugging multiple engines.
+            arguments << QLatin1String(Constants::QMAKEVAR_QUICK1_DEBUG);
+            if (version->qtVersion().majorVersion >= 5) {
+                arguments << QLatin1String(Constants::QMAKEVAR_QUICK2_DEBUG);
+            }
         } else {
             const QString qmlDebuggingHelperLibrary = version->qmlDebuggingHelperLibrary(true);
             if (!qmlDebuggingHelperLibrary.isEmpty()) {
diff --git a/src/plugins/qt4projectmanager/qt4buildconfiguration.cpp b/src/plugins/qt4projectmanager/qt4buildconfiguration.cpp
index a17fa4d4b6b205e23e4a59f485a4055fc4ce7169..5b2b8f247f7dc8e194dd5815d30524a7f1bbd9a0 100644
--- a/src/plugins/qt4projectmanager/qt4buildconfiguration.cpp
+++ b/src/plugins/qt4projectmanager/qt4buildconfiguration.cpp
@@ -436,8 +436,8 @@ bool Qt4BuildConfiguration::removeQMLInspectorFromArguments(QString *args)
     for (Utils::QtcProcess::ArgIterator ait(args); ait.next(); ) {
         const QString arg = ait.value();
         if (arg.contains(QLatin1String(Constants::QMAKEVAR_QMLJSDEBUGGER_PATH))
-            || arg.contains(QLatin1String(Constants::QMAKEVAR_DECLARATIVE_DEBUG4))
-            || arg.contains(QLatin1String(Constants::QMAKEVAR_DECLARATIVE_DEBUG5))) {
+            || arg.contains(QLatin1String(Constants::QMAKEVAR_QUICK1_DEBUG))
+            || arg.contains(QLatin1String(Constants::QMAKEVAR_QUICK2_DEBUG))) {
             ait.deleteArg();
             removedArgument = true;
         }
diff --git a/src/plugins/qt4projectmanager/qt4projectmanagerconstants.h b/src/plugins/qt4projectmanager/qt4projectmanagerconstants.h
index 1710c0bfb27c416c6fd55bef253d1df791285b75..ebb77f1789d390bd06b9a5fc007b6f6e50be4f0f 100644
--- a/src/plugins/qt4projectmanager/qt4projectmanagerconstants.h
+++ b/src/plugins/qt4projectmanager/qt4projectmanagerconstants.h
@@ -89,8 +89,8 @@ const char ICON_HTML5_APP[] = ":/wizards/images/html5app.png";
 
 // Env variables
 const char QMAKEVAR_QMLJSDEBUGGER_PATH[] = "QMLJSDEBUGGER_PATH";
-const char QMAKEVAR_DECLARATIVE_DEBUG4[] = "CONFIG+=declarative_debug";
-const char QMAKEVAR_DECLARATIVE_DEBUG5[] = "CONFIG+=qml_debug";
+const char QMAKEVAR_QUICK1_DEBUG[] = "CONFIG+=declarative_debug";
+const char QMAKEVAR_QUICK2_DEBUG[] = "CONFIG+=qml_debug";
 
 // Unconfigured Panel
 const char UNCONFIGURED_PANEL_PAGE_ID[] = "UnconfiguredPanel";