diff --git a/c++/carla-backend/carla_backend.h b/c++/carla-backend/carla_backend.h
index 4024318..92545d5 100644
--- a/c++/carla-backend/carla_backend.h
+++ b/c++/carla-backend/carla_backend.h
@@ -49,13 +49,14 @@ const unsigned int MAX_PARAMETERS = 200; //!< Default value for the maximum numb
  * \see CarlaPlugin::hints()
  * @{
  */
-const unsigned int PLUGIN_IS_BRIDGE   = 0x01; //!< Plugin is a bridge (ie, BridgePlugin). This hint is required because "bridge" itself is not a plugin type.
-const unsigned int PLUGIN_IS_SYNTH    = 0x02; //!< Plugin is a synthesizer (produces sound).
-const unsigned int PLUGIN_HAS_GUI     = 0x04; //!< Plugin has its own custom GUI.
-const unsigned int PLUGIN_USES_CHUNKS = 0x08; //!< Plugin uses chunks to save internal data.\see CarlaPlugin::chunkData()
-const unsigned int PLUGIN_CAN_DRYWET  = 0x10; //!< Plugin can make use of Dry/Wet controls.
-const unsigned int PLUGIN_CAN_VOLUME  = 0x20; //!< Plugin can make use of Volume controls.
-const unsigned int PLUGIN_CAN_BALANCE = 0x40; //!< Plugin can make use of Left & Right Balance controls.
+const unsigned int PLUGIN_IS_BRIDGE          = 0x01; //!< Plugin is a bridge (ie, BridgePlugin). This hint is required because "bridge" itself is not a plugin type.
+const unsigned int PLUGIN_IS_SYNTH           = 0x02; //!< Plugin is a synthesizer (produces sound).
+const unsigned int PLUGIN_HAS_GUI            = 0x04; //!< Plugin has its own custom GUI.
+const unsigned int PLUGIN_USES_CHUNKS        = 0x08; //!< Plugin uses chunks to save internal data.\see CarlaPlugin::chunkData()
+const unsigned int PLUGIN_USES_SINGLE_THREAD = 0x10; //!< Plugin has its own custom GUI.
+const unsigned int PLUGIN_CAN_DRYWET         = 0x20; //!< Plugin can make use of Dry/Wet controls.
+const unsigned int PLUGIN_CAN_VOLUME         = 0x40; //!< Plugin can make use of Volume controls.
+const unsigned int PLUGIN_CAN_BALANCE        = 0x80; //!< Plugin can make use of Left & Right Balance controls.
 /**@}*/
 
 /*!
diff --git a/c++/carla-backend/carla_engine.h b/c++/carla-backend/carla_engine.h
index 6e9b5b8..bd43ea3 100644
--- a/c++/carla-backend/carla_engine.h
+++ b/c++/carla-backend/carla_engine.h
@@ -187,6 +187,7 @@ public:
 
     short        getNewPluginId() const;
     CarlaPlugin* getPlugin(const unsigned short id) const;
+    CarlaPlugin* getPluginUnchecked(const unsigned short id) const { return m_carlaPlugins[id]; }
     const char*  getUniqueName(const char* const name);
 
     short addPlugin(const BinaryType btype, const PluginType ptype, const char* const filename, const char* const name, const char* const label, void* const extra = nullptr);
@@ -202,11 +203,6 @@ public:
         m_carlaPlugins[id] = plugin;
     }
 
-    CarlaPlugin* __getPlugin(const unsigned short id) const
-    {
-        return m_carlaPlugins[id];
-    }
-
     // -------------------------------------------------------------------
     // Information (base)
 
diff --git a/c++/carla-backend/carla_engine_jack.cpp b/c++/carla-backend/carla_engine_jack.cpp
index b999245..de36298 100644
--- a/c++/carla-backend/carla_engine_jack.cpp
+++ b/c++/carla-backend/carla_engine_jack.cpp
@@ -317,7 +317,7 @@ void CarlaEngineJack::handleProcessCallback(uint32_t nframes)
     {
         for (unsigned short i=0; i < MAX_PLUGINS; i++)
         {
-            CarlaPlugin* const plugin = __getPlugin(i);
+            CarlaPlugin* const plugin = getPluginUnchecked(i);
 
             if (plugin && plugin->enabled())
             {
@@ -451,7 +451,7 @@ void CarlaEngineJack::handleProcessCallback(uint32_t nframes)
         // process plugins
         for (unsigned short i=0; i < MAX_PLUGINS; i++)
         {
-            CarlaPlugin* const plugin = __getPlugin(i);
+            CarlaPlugin* const plugin = getPluginUnchecked(i);
 
             if (plugin && plugin->enabled())
             {
diff --git a/c++/carla-backend/carla_engine_rtaudio.cpp b/c++/carla-backend/carla_engine_rtaudio.cpp
index 9befcc0..4107c6f 100644
--- a/c++/carla-backend/carla_engine_rtaudio.cpp
+++ b/c++/carla-backend/carla_engine_rtaudio.cpp
@@ -207,7 +207,7 @@ void CarlaEngineRtAudio::handleProcessCallback(void* outputBuffer, void* inputBu
     // process plugins
     for (unsigned short i=0; i < MAX_PLUGINS; i++)
     {
-        CarlaPlugin* const plugin = __getPlugin(i);
+        CarlaPlugin* const plugin = getPluginUnchecked(i);
 
         if (plugin && plugin->enabled())
         {
diff --git a/c++/carla-backend/carla_osc.cpp b/c++/carla-backend/carla_osc.cpp
index 5b0ddd6..d152786 100644
--- a/c++/carla-backend/carla_osc.cpp
+++ b/c++/carla-backend/carla_osc.cpp
@@ -265,7 +265,7 @@ int CarlaOsc::handle_register(const int argc, const lo_arg* const* const argv, c
 
     for (unsigned short i=0; i < CarlaBackend::MAX_PLUGINS; i++)
     {
-        CarlaBackend::CarlaPlugin* const plugin = engine->__getPlugin(i);
+        CarlaBackend::CarlaPlugin* const plugin = engine->getPluginUnchecked(i);
 
         if (plugin && plugin->enabled())
             plugin->registerToOsc();
diff --git a/c++/carla-backend/carla_plugin.h b/c++/carla-backend/carla_plugin.h
index d6c2282..558da7c 100644
--- a/c++/carla-backend/carla_plugin.h
+++ b/c++/carla-backend/carla_plugin.h
@@ -503,6 +503,18 @@ public:
         return &param.ranges[parameterId];
     }
 
+    /*!
+     * Check if a parameter is out output type.
+     *
+     * \see PARAMETER_OUTPUT
+     */
+    bool parameterIsOutput(uint32_t parameterId) const
+    {
+        Q_ASSERT(parameterId < param.count);
+
+        return (param.data[parameterId].type == PARAMETER_OUTPUT);
+    }
+
     /*!
      * Get the MIDI program at \a index.
      *
@@ -695,21 +707,17 @@ public:
      */
     void getParameterCountInfo(uint32_t* ins, uint32_t* outs, uint32_t* total)
     {
-        uint32_t _ins   = 0;
-        uint32_t _outs  = 0;
-        uint32_t _total = param.count;
+        *ins   = 0;
+        *outs  = 0;
+        *total = param.count;
 
         for (uint32_t i=0; i < param.count; i++)
         {
             if (param.data[i].type == PARAMETER_INPUT)
-                _ins += 1;
+                *ins += 1;
             else if (param.data[i].type == PARAMETER_OUTPUT)
-                _outs += 1;
+                *outs += 1;
         }
-
-        *ins   = _ins;
-        *outs  = _outs;
-        *total = _total;
     }
 
     /*!
@@ -1252,36 +1260,19 @@ public:
      */
     virtual void idleGui()
     {
-        m_needsParamUpdate = false;
-        m_needsProgUpdate = false;
-
         if (! m_enabled)
             return;
 
-        // -------------------------------------------------------
-        // Process postponed events
-
-        postEventsRun();
-
-        // -------------------------------------------------------
-        // Update parameters (OSC)
-
-        updateOscParameterOutputs();
-
-        // -------------------------------------------------------
-        // Send peak values (OSC)
-
-        if (x_engine->isOscControllerRegisted())
+        if (m_hints & PLUGIN_USES_SINGLE_THREAD)
         {
-            if (audioInCount() > 0)
-            {
-                x_engine->osc_send_set_input_peak_value(m_id, 1, x_engine->getInputPeak(m_id, 0));
-                x_engine->osc_send_set_input_peak_value(m_id, 2, x_engine->getInputPeak(m_id, 1));
-            }
-            if (audioOutCount() > 0)
+            // Process postponed events
+            postEventsRun();
+
+            // Update parameter outputs
+            for (uint32_t i=0; i < param.count; i++)
             {
-                x_engine->osc_send_set_output_peak_value(m_id, 1, x_engine->getOutputPeak(m_id, 0));
-                x_engine->osc_send_set_output_peak_value(m_id, 2, x_engine->getOutputPeak(m_id, 1));
+                if (param.data[i].type == PARAMETER_OUTPUT)
+                    uiParameterChange(i, getParameterValue(i));
             }
         }
     }
@@ -1550,34 +1541,6 @@ public:
         }
     }
 
-    /*!
-     * TODO
-     */
-    void updateOscParameterOutputs()
-    {
-        // Check if it needs update
-        bool updatePortsGui = (osc.data.target && (m_hints & PLUGIN_IS_BRIDGE) == 0);
-
-        if (! (x_engine->isOscControllerRegisted() || updatePortsGui))
-            return;
-
-        // Update
-        double value;
-
-        for (uint32_t i=0; i < param.count; i++)
-        {
-            if (param.data[i].type == PARAMETER_OUTPUT /*&& (paramData->hints & PARAMETER_IS_AUTOMABLE) > 0*/)
-            {
-                value = getParameterValue(i);
-
-                if (updatePortsGui)
-                    osc_send_control(&osc.data, param.data[i].rindex, value);
-
-                x_engine->osc_send_set_parameter_value(m_id, i, value);
-            }
-        }
-    }
-
     /*!
      * Clear the plugin's internal OSC data.
      */
@@ -1744,16 +1707,15 @@ public:
             switch (event->type)
             {
             case PluginPostEventNull:
-                return;
+                break;
 
             case PluginPostEventDebug:
                 x_engine->callback(CALLBACK_DEBUG, m_id, event->value1, event->value2, event->value3);
                 break;
 
             case PluginPostEventParameterChange:
-                // Update OSC based UIs
-                m_needsParamUpdate = true;
-                osc_send_control(&osc.data, event->value1, event->value3);
+                // Update UI
+                uiParameterChange(event->value1, event->value3);
 
                 // Update OSC control client
                 x_engine->osc_send_set_parameter_value(m_id, event->value1, event->value3);
@@ -1763,9 +1725,8 @@ public:
                 break;
 
             case PluginPostEventProgramChange:
-                // Update OSC based UIs
-                m_needsProgUpdate = true;
-                osc_send_program(&osc.data, event->value1);
+                // Update UI
+                uiProgramChange(event->value1);
 
                 // Update OSC control client
                 x_engine->osc_send_set_program(m_id, event->value1);
@@ -1778,16 +1739,8 @@ public:
                 break;
 
             case PluginPostEventMidiProgramChange:
-                // Update OSC based UIs
-                m_needsProgUpdate = true;
-
-                if (m_type == PLUGIN_DSSI)
-                {
-                    if (event->value1 >= 0 && event->value1 < (int32_t)midiprog.count)
-                        osc_send_program(&osc.data, midiprog.data[event->value1].bank, midiprog.data[event->value1].program);
-                }
-                else
-                    osc_send_midi_program(&osc.data, event->value1);
+                // Update UI
+                uiMidiProgramChange(event->value1);
 
                 // Update OSC control client
                 x_engine->osc_send_set_midi_program(m_id, event->value1);
@@ -1797,19 +1750,11 @@ public:
 
                 // Update Host
                 x_engine->callback(CALLBACK_MIDI_PROGRAM_CHANGED, m_id, event->value1, 0, 0.0);
-                //}
                 break;
 
             case PluginPostEventNoteOn:
-                // Update OSC based UIs
-                if (osc.data.target)
-                {
-                    uint8_t midiData[4] = { 0 };
-                    midiData[1] = MIDI_STATUS_NOTE_ON + event->value1;
-                    midiData[2] = event->value2;
-                    midiData[3] = rint(event->value3);
-                    osc_send_midi(&osc.data, midiData);
-                }
+                // Update UI
+                uiNoteOn(event->value1, event->value2, rint(event->value3));
 
                 // Update OSC control client
                 x_engine->osc_send_note_on(m_id, event->value1, event->value2, event->value3);
@@ -1819,14 +1764,8 @@ public:
                 break;
 
             case PluginPostEventNoteOff:
-                // Update OSC based UIs
-                if (osc.data.target)
-                {
-                    uint8_t midiData[4] = { 0 };
-                    midiData[1] = MIDI_STATUS_NOTE_OFF + event->value1;
-                    midiData[2] = event->value2;
-                    osc_send_midi(&osc.data, midiData);
-                }
+                // Update UI
+                uiNoteOff(event->value1, event->value2);
 
                 // Update OSC control client
                 x_engine->osc_send_note_off(m_id, event->value1, event->value2);
@@ -1838,6 +1777,53 @@ public:
         }
     }
 
+    /*!
+     * TODO
+     */
+    virtual void uiParameterChange(uint32_t index, double value)
+    {
+        Q_ASSERT(index < param.count);
+        Q_UNUSED(index);
+        Q_UNUSED(value);
+    }
+
+    /*!
+     * TODO
+     */
+    virtual void uiProgramChange(uint32_t index)
+    {
+        Q_ASSERT(index < prog.count);
+        Q_UNUSED(index);
+    }
+
+    /*!
+     * TODO
+     */
+    virtual void uiMidiProgramChange(uint32_t index)
+    {
+        Q_ASSERT(index < midiprog.count);
+        Q_UNUSED(index);
+    }
+
+    /*!
+     * TODO
+     */
+    virtual void uiNoteOn(uint8_t channel, uint8_t note, uint8_t velo)
+    {
+        Q_UNUSED(channel);
+        Q_UNUSED(note);
+        Q_UNUSED(velo);
+    }
+
+    /*!
+     * TODO
+     */
+    virtual void uiNoteOff(uint8_t channel, uint8_t note)
+    {
+        Q_UNUSED(channel);
+        Q_UNUSED(note);
+    }
+
     // -------------------------------------------------------------------
     // Cleanup
 
@@ -2048,11 +2034,10 @@ public:
     // -------------------------------------------------------------------
 
 protected:
-    // static
     unsigned short m_id;
     CarlaEngine* const x_engine;
+    CarlaEngineClient* x_client;
 
-    // non-static
     PluginType m_type;
     unsigned int m_hints;
 
@@ -2067,10 +2052,6 @@ protected:
     int8_t cin_channel;
 
     double x_drywet, x_vol, x_bal_left, x_bal_right;
-    CarlaEngineClient* x_client;
-
-    bool m_needsParamUpdate;
-    bool m_needsProgUpdate;
 
     // -------------------------------------------------------------------
     // Storage Data
diff --git a/c++/carla-backend/carla_threads.cpp b/c++/carla-backend/carla_threads.cpp
index 6920b11..caa6aee 100644
--- a/c++/carla-backend/carla_threads.cpp
+++ b/c++/carla-backend/carla_threads.cpp
@@ -40,6 +40,9 @@ void CarlaCheckThread::stopNow()
 {
     m_stopNow = true;
 
+    // TESTING - let processing finish first
+    QMutexLocker(&this->mutex); // FIXME
+
     if (isRunning() && ! wait(200))
     {
         quit();
@@ -53,32 +56,60 @@ void CarlaCheckThread::run()
 {
     qDebug("CarlaCheckThread::run()");
 
+    bool oscControllerRegisted, usesSingleThread;
+    unsigned short id;
+    double value;
+
     m_stopNow = false;
+
     while (engine->isRunning() && ! m_stopNow)
     {
+        QMutexLocker(&this->mutex); // FIXME
+        oscControllerRegisted = engine->isOscControllerRegisted();
+
         for (unsigned short i=0; i < CarlaBackend::MAX_PLUGINS; i++)
         {
-            CarlaBackend::CarlaPlugin* const plugin = engine->__getPlugin(i);
+            CarlaBackend::CarlaPlugin* const plugin = engine->getPluginUnchecked(i);
 
             if (plugin && plugin->enabled())
             {
+                id = plugin->id();
+                usesSingleThread = (plugin->hints() & CarlaBackend::PLUGIN_USES_SINGLE_THREAD);
+
                 // -------------------------------------------------------
                 // Process postponed events
 
-                plugin->postEventsRun();
+                if (! usesSingleThread)
+                    plugin->postEventsRun();
 
                 // -------------------------------------------------------
-                // Update parameters (OSC)
+                // Update parameter outputs
 
-                plugin->updateOscParameterOutputs();
+                if (oscControllerRegisted || ! usesSingleThread)
+                {
+                    for (uint32_t i=0; i < plugin->parameterCount(); i++)
+                    {
+                        if (plugin->parameterIsOutput(i))
+                        {
+                            value = plugin->getParameterValue(i);
+
+                            // Update UI
+                            if (! usesSingleThread)
+                                plugin->uiParameterChange(i, value);
+
+                            // Update OSC control client
+                            if (oscControllerRegisted)
+                                engine->osc_send_set_parameter_value(id, i, value);
+                        }
+                    }
+                }
 
                 // -------------------------------------------------------
-                // Send peak values (OSC)
+                // Update OSC control client
 
-                if (engine->isOscControllerRegisted())
+                if (oscControllerRegisted)
                 {
-                    const unsigned short id = plugin->id();
-
+                    // Peak values
                     if (plugin->audioInCount() > 0)
                     {
                         engine->osc_send_set_input_peak_value(id, 1, engine->getInputPeak(id, 0));
@@ -146,7 +177,7 @@ void CarlaPluginThread::run()
 {
     qDebug("CarlaPluginThread::run()");
 
-    if (m_process == nullptr)
+    if (! m_process)
         m_process = new QProcess(nullptr);
 
     m_process->setProcessChannelMode(QProcess::ForwardedChannels);
@@ -156,21 +187,21 @@ void CarlaPluginThread::run()
     switch (mode)
     {
     case PLUGIN_THREAD_DSSI_GUI:
-        /* osc_url  */ arguments << QString("%1/%2").arg(engine->getOscServerPath()).arg(plugin->id());
+        /* osc_url  */ arguments << QString("%1/%2").arg(engine->getOscServerPath(), plugin->id());
         /* filename */ arguments << plugin->filename();
         /* label    */ arguments << m_label;
         /* ui-title */ arguments << QString("%1 (GUI)").arg(plugin->name());
         break;
 
     case PLUGIN_THREAD_LV2_GUI:
-        /* osc_url  */ arguments << QString("%1/%2").arg(engine->getOscServerPath()).arg(plugin->id());
+        /* osc_url  */ arguments << QString("%1/%2").arg(engine->getOscServerPath(), plugin->id());
         /* URI      */ arguments << m_label;
         /* ui-URI   */ arguments << m_data1;
         /* ui-title */ arguments << QString("%1 (GUI)").arg(plugin->name());
         break;
 
     case PLUGIN_THREAD_VST_GUI:
-        /* osc_url  */ arguments << QString("%1/%2").arg(engine->getOscServerPath()).arg(plugin->id());
+        /* osc_url  */ arguments << QString("%1/%2").arg(engine->getOscServerPath(), plugin->id());
         /* filename */ arguments << plugin->filename();
         /* label    */ arguments << m_label;
         /* ui-title */ arguments << QString("%1 (GUI)").arg(plugin->name());
@@ -183,7 +214,7 @@ void CarlaPluginThread::run()
         if (! name)
             name = "(none)";
 
-        /* osc_url  */ arguments << QString("%1/%2").arg(engine->getOscServerPath()).arg(plugin->id());
+        /* osc_url  */ arguments << QString("%1/%2").arg(engine->getOscServerPath(), plugin->id());
         /* stype    */ arguments << m_data1;
         /* filename */ arguments << plugin->filename();
         /* name     */ arguments << name;
diff --git a/c++/carla-backend/carla_threads.h b/c++/carla-backend/carla_threads.h
index 89a8f71..6e907b9 100644
--- a/c++/carla-backend/carla_threads.h
+++ b/c++/carla-backend/carla_threads.h
@@ -20,6 +20,7 @@
 
 #include "carla_backend.h"
 
+#include <QtCore/QMutex>
 #include <QtCore/QThread>
 
 class QProcess;
@@ -35,11 +36,22 @@ public:
 
     void stopNow();
 
+    void lock()
+    {
+        mutex.lock();
+    }
+
+    void unlock()
+    {
+        mutex.unlock();
+    }
+
 protected:
     void run();
 
 private:
     CarlaBackend::CarlaEngine* const engine;
+    QMutex mutex;
     bool m_stopNow;
 };
 
diff --git a/c++/carla-backend/dssi.cpp b/c++/carla-backend/dssi.cpp
index 84fcb57..cb0ab6c 100644
--- a/c++/carla-backend/dssi.cpp
+++ b/c++/carla-backend/dssi.cpp
@@ -1325,6 +1325,54 @@ public:
         m_activeBefore = m_active;
     }
 
+    // -------------------------------------------------------------------
+    // Post-poned events
+
+    void uiParameterChange(uint32_t index, double value)
+    {
+        Q_ASSERT(index < param.count);
+        if (index >= param.count)
+            return;
+        if (! osc.data.target)
+            return;
+
+        osc_send_control(&osc.data, param.data[index].rindex, value);
+    }
+
+    void uiMidiProgramChange(uint32_t index)
+    {
+        Q_ASSERT(index < midiprog.count);
+        if (index >= midiprog.count)
+            return;
+        if (! osc.data.target)
+            return;
+
+        osc_send_program(&osc.data, midiprog.data[index].bank, midiprog.data[index].program);
+    }
+
+    void uiNoteOn(uint8_t channel, uint8_t note, uint8_t velo)
+    {
+        if (! osc.data.target)
+            return;
+
+        uint8_t midiData[4] = { 0 };
+        midiData[1] = MIDI_STATUS_NOTE_ON + channel;
+        midiData[2] = note;
+        midiData[3] = velo;
+        osc_send_midi(&osc.data, midiData);
+    }
+
+    void uiNoteOff(uint8_t channel, uint8_t note)
+    {
+        if (! osc.data.target)
+            return;
+
+        uint8_t midiData[4] = { 0 };
+        midiData[1] = MIDI_STATUS_NOTE_OFF + channel;
+        midiData[2] = note;
+        osc_send_midi(&osc.data, midiData);
+    }
+
     // -------------------------------------------------------------------
     // Cleanup
 
diff --git a/c++/carla-backend/lv2.cpp b/c++/carla-backend/lv2.cpp
index aea6884..eee3aa1 100644
--- a/c++/carla-backend/lv2.cpp
+++ b/c++/carla-backend/lv2.cpp
@@ -907,27 +907,11 @@ public:
 
     void idleGui()
     {
-        if (ui.handle && ui.descriptor && gui.type != GUI_EXTERNAL_OSC)
-        {
-            // Update output port values
-            if (ui.descriptor->port_event)
-            {
-                float value;
+        // Update external UI
+        if (ui.handle && ui.descriptor && ui.widget && gui.type == GUI_EXTERNAL_LV2)
+            LV2_EXTERNAL_UI_RUN((lv2_external_ui*)ui.widget);
 
-                for (uint32_t i=0; i < param.count; i++)
-                {
-                    if (param.data[i].type == PARAMETER_OUTPUT)
-                    {
-                        value = getParameterValue(i);
-                        ui.descriptor->port_event(ui.handle, param.data[i].rindex, sizeof(float), 0, &value);
-                    }
-                }
-            }
-
-            // Update UI
-            if (ui.widget && gui.type == GUI_EXTERNAL_LV2)
-                LV2_EXTERNAL_UI_RUN((lv2_external_ui*)ui.widget);
-        }
+        CarlaPlugin::idleGui();
     }
 
     // -------------------------------------------------------------------
@@ -2300,6 +2284,51 @@ public:
         m_activeBefore = m_active;
     }
 
+    // -------------------------------------------------------------------
+    // Post-poned events
+
+    void uiParameterChange(uint32_t index, double value)
+    {
+        Q_ASSERT(index < param.count);
+        if (index >= param.count)
+            return;
+
+        if (osc.data.target)
+            osc_send_control(&osc.data, param.data[index].rindex, value);
+        else if (ui.handle && ui.descriptor && ui.descriptor->port_event)
+        {
+            float valuef = value;
+            ui.descriptor->port_event(ui.handle, param.data[index].rindex, sizeof(float), 0, &valuef);
+        }
+    }
+
+    void uiMidiProgramChange(uint32_t index)
+    {
+        Q_ASSERT(index < midiprog.count);
+        if (index >= midiprog.count)
+            return;
+
+        if (osc.data.target)
+            osc_send_program(&osc.data, midiprog.data[index].bank, midiprog.data[index].program);
+        else if (ext.uiprograms)
+            ext.uiprograms->select_program(ui.handle, midiprog.data[index].bank, midiprog.data[index].program);
+    }
+
+    void uiNoteOn(uint8_t channel, uint8_t note, uint8_t velo)
+    {
+        // TODO
+        Q_UNUSED(channel);
+        Q_UNUSED(note);
+        Q_UNUSED(velo);
+    }
+
+    void uiNoteOff(uint8_t channel, uint8_t note)
+    {
+        // TODO
+        Q_UNUSED(channel);
+        Q_UNUSED(note);
+    }
+
     // -------------------------------------------------------------------
     // Cleanup
 
@@ -3662,6 +3691,7 @@ public:
                     gui.type      = GUI_INTERNAL_QT4;
                     gui.resizable = isUiResizable();
                     ui.handle     = ui.descriptor->instantiate(ui.descriptor, descriptor->URI, ui.rdf_descriptor->Bundle, carla_lv2_ui_write_function, this, &ui.widget, features);
+                    m_hints      |= PLUGIN_USES_SINGLE_THREAD;
                     updateUi();
                     break;
 
@@ -3689,6 +3719,7 @@ public:
                     gui.type      = GUI_EXTERNAL_SUIL;
                     gui.resizable = isUiResizable();
                     suil.handle   = suil_instance_new(suil.host, this, LV2_UI__Qt4UI, rdf_descriptor->URI, ui.rdf_descriptor->URI, get_lv2_ui_uri(ui.rdf_descriptor->Type), ui.rdf_descriptor->Bundle, ui.rdf_descriptor->Binary, features);
+                    m_hints      |= PLUGIN_USES_SINGLE_THREAD;
 
                     if (suil.handle)
                     {
diff --git a/c++/carla-backend/vst.cpp b/c++/carla-backend/vst.cpp
index 5304a36..cdf2d9b 100644
--- a/c++/carla-backend/vst.cpp
+++ b/c++/carla-backend/vst.cpp
@@ -312,6 +312,8 @@ public:
         // FIXME
         if (gui.visible)
             effect->dispatcher(effect, effEditIdle, 0, 0, nullptr, 0.0f);
+
+        CarlaPlugin::idleGui();
     }
 
     // -------------------------------------------------------------------
diff --git a/c++/xycontroller/xycontroller.cpp b/c++/xycontroller/xycontroller.cpp
index 6d95aaa..2b866cc 100644
--- a/c++/xycontroller/xycontroller.cpp
+++ b/c++/xycontroller/xycontroller.cpp
@@ -171,7 +171,7 @@ private:
             : d1(0), d2(0), d3(0) {}
     };
 
-    static const unsigned short MAX_SIZE = 128;
+    static const unsigned short MAX_SIZE = 512;
     datatype data[MAX_SIZE];
     unsigned short index;
     bool empty, full;
diff --git a/src/shared_carla.py b/src/shared_carla.py
index 14ccae3..64b12f2 100644
--- a/src/shared_carla.py
+++ b/src/shared_carla.py
@@ -53,13 +53,14 @@ MAX_PLUGINS    = 99
 MAX_PARAMETERS = 200
 
 # plugin hints
-PLUGIN_IS_BRIDGE   = 0x01
-PLUGIN_IS_SYNTH    = 0x02
-PLUGIN_HAS_GUI     = 0x04
-PLUGIN_USES_CHUNKS = 0x08
-PLUGIN_CAN_DRYWET  = 0x10
-PLUGIN_CAN_VOLUME  = 0x20
-PLUGIN_CAN_BALANCE = 0x40
+PLUGIN_IS_BRIDGE          = 0x01
+PLUGIN_IS_SYNTH           = 0x02
+PLUGIN_HAS_GUI            = 0x04
+PLUGIN_USES_CHUNKS        = 0x08
+PLUGIN_USES_SINGLE_THREAD = 0x10
+PLUGIN_CAN_DRYWET         = 0x20
+PLUGIN_CAN_VOLUME         = 0x40
+PLUGIN_CAN_BALANCE        = 0x80
 
 # parameter hints
 PARAMETER_IS_BOOLEAN       = 0x01