diff --git a/.github/workflows/checks.yml b/.github/workflows/checks.yml
index 05d078205..1d893989e 100644
--- a/.github/workflows/checks.yml
+++ b/.github/workflows/checks.yml
@@ -5,7 +5,7 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 jobs:
-  check-strings:
+  scripted-checks:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
@@ -17,6 +17,8 @@ jobs:
         run: tests/scripted/verify
       - name: Run check-strings
         run: tests/scripted/check-strings
+      - name: Run check-namespace
+        run: tests/scripted/check-namespace
   shellcheck:
     runs-on: ubuntu-latest
     container: koalaman/shellcheck-alpine:v0.4.6
diff --git a/include/AudioPortAudio.h b/include/AudioPortAudio.h
index e6750e4b4..3fd32a7ac 100644
--- a/include/AudioPortAudio.h
+++ b/include/AudioPortAudio.h
@@ -143,7 +143,7 @@ private:
 		void *hostApiSpecificStreamInfo;
 
 	} PaStreamParameters;
-#endif
+#endif // PORTAUDIO_V19
 
 	PaStream * m_paStream;
 	PaStreamParameters m_outputParameters;
diff --git a/include/AudioPulseAudio.h b/include/AudioPulseAudio.h
index a4721dfbd..789296e27 100644
--- a/include/AudioPulseAudio.h
+++ b/include/AudioPulseAudio.h
@@ -102,6 +102,6 @@ private:
 
 } // namespace lmms
 
-#endif
+#endif // LMMS_HAVE_PULSEAUDIO
 
 #endif
diff --git a/include/AudioSndio.h b/include/AudioSndio.h
index b2da8eac0..606850105 100644
--- a/include/AudioSndio.h
+++ b/include/AudioSndio.h
@@ -87,6 +87,6 @@ private:
 
 } // namespace lmms
 
-#endif	/* LMMS_HAVE_SNDIO */
+#endif	// LMMS_HAVE_SNDIO
 
-#endif	/* _AUDIO_SNDIO_H */
+#endif	// _AUDIO_SNDIO_H
diff --git a/include/DummyEffect.h b/include/DummyEffect.h
index 675249865..9db45a3e1 100644
--- a/include/DummyEffect.h
+++ b/include/DummyEffect.h
@@ -50,7 +50,7 @@ public:
 
 } ;
 
-}
+} // namespace gui
 
 class DummyEffectControls : public EffectControls
 {
diff --git a/include/DummyPlugin.h b/include/DummyPlugin.h
index cf36d2159..1c763ec3e 100644
--- a/include/DummyPlugin.h
+++ b/include/DummyPlugin.h
@@ -66,6 +66,6 @@ protected:
 } ;
 
 
-} // namesplace lmms
+} // namespace lmms
 
 #endif
diff --git a/include/IoHelper.h b/include/IoHelper.h
index 4f08f5087..c7d65c917 100644
--- a/include/IoHelper.h
+++ b/include/IoHelper.h
@@ -22,6 +22,8 @@
  *
  */
 
+#ifndef IO_HELPER_H
+#define IO_HELPER_H
 
 #include "lmmsconfig.h"
 
@@ -37,7 +39,7 @@
 #ifdef LMMS_HAVE_UNISTD_H
 #include <unistd.h>
 #endif
-#endif
+#endif // LMMS_BUILD_WIN32
 
 namespace lmms
 {
@@ -87,4 +89,6 @@ int fileToDescriptor(FILE* f, bool closeFile = true)
 }
 
 
-} // namespace lmms
\ No newline at end of file
+} // namespace lmms
+
+#endif
diff --git a/include/LmmsPalette.h b/include/LmmsPalette.h
index b07aa5c84..023872254 100644
--- a/include/LmmsPalette.h
+++ b/include/LmmsPalette.h
@@ -23,12 +23,12 @@
  *
  */
 
-#include <QWidget>
-#include "lmms_export.h"
-
 #ifndef LMMSPALETTE_H
 #define LMMSPALETTE_H
 
+#include <QWidget>
+#include "lmms_export.h"
+
 
 namespace lmms::gui
 {
diff --git a/include/MidiSndio.h b/include/MidiSndio.h
index 35788131d..3ebd14d05 100644
--- a/include/MidiSndio.h
+++ b/include/MidiSndio.h
@@ -73,6 +73,6 @@ private:
 
 } // namespace lmms
 
-#endif	/* LMMS_HAVE_SNDIO */
+#endif // LMMS_HAVE_SNDIO
 
-#endif	/* _MIDI_SNDIO_H */
+#endif	// _MIDI_SNDIO_H
diff --git a/include/RemotePluginBase.h b/include/RemotePluginBase.h
index 0a3601d7c..e309496bc 100644
--- a/include/RemotePluginBase.h
+++ b/include/RemotePluginBase.h
@@ -341,7 +341,7 @@ private:
 	std::atomic_int m_lockDepth;
 
 } ;
-#endif
+#endif // SYNC_WITH_SHM_FIFO
 
 
 
@@ -530,7 +530,7 @@ public:
 		writeInt( len );
 		write( _s.c_str(), len );
 	}
-#endif
+#endif // SYNC_WITH_SHM_FIFO
 
 #ifndef BUILD_REMOTE_PLUGIN_CLIENT
 	inline bool messagesLeft()
@@ -562,7 +562,7 @@ public:
 	{
 		return waitDepthCounter() > 0;
 	}
-#endif
+#endif // BUILD_REMOTE_PLUGIN_CLIENT
 
 	virtual bool processMessage( const message & _m ) = 0;
 
@@ -667,7 +667,7 @@ private:
 
 	pthread_mutex_t m_receiveMutex;
 	pthread_mutex_t m_sendMutex;
-#endif
+#endif // SYNC_WITH_SHM_FIFO
 
 } ;
 
diff --git a/include/RemotePluginClient.h b/include/RemotePluginClient.h
index 2d825486e..4c5fcc060 100644
--- a/include/RemotePluginClient.h
+++ b/include/RemotePluginClient.h
@@ -173,7 +173,7 @@ private:
 	std::condition_variable m_cv;
 	std::thread m_thread;
 };
-#endif
+#endif // LMMS_BUILD_WIN32
 
 #ifdef SYNC_WITH_SHM_FIFO
 RemotePluginClient::RemotePluginClient( const std::string& _shm_in, const std::string& _shm_out ) :
diff --git a/include/debug.h b/include/debug.h
index f619da666..f2ea29cc1 100644
--- a/include/debug.h
+++ b/include/debug.h
@@ -33,7 +33,7 @@
 #ifndef NDEBUG
 	#define NDEBUG
 #endif
-#endif
+#endif // LMMS_DEBUG
 
 #include <cassert>
 #include <cstdio>
diff --git a/include/embed.h b/include/embed.h
index c8914ba47..03d767b43 100644
--- a/include/embed.h
+++ b/include/embed.h
@@ -65,7 +65,7 @@ inline QPixmap getIconPixmap( const QString&  _name,
 }
 //QString getText( const char * _name );
 
-}
+} // namespace PLUGIN_NAME
 
 #endif // PLUGIN_NAME
 
diff --git a/include/lmms_math.h b/include/lmms_math.h
index e1de09936..db4502f1c 100644
--- a/include/lmms_math.h
+++ b/include/lmms_math.h
@@ -118,7 +118,7 @@ static inline float absFraction( float _x )
 }
 #endif
 
-#endif
+#endif // __INTEL_COMPILER
 
 
 
@@ -153,7 +153,7 @@ static inline long double fastFmal( long double a, long double b, long double c
 	#endif
 #else
 	return a * b + c;
-#endif
+#endif // FP_FAST_FMAL
 }
 
 //! @brief Takes advantage of fmaf() function if present in hardware
@@ -167,7 +167,7 @@ static inline float fastFmaf( float a, float b, float c )
 	#endif
 #else
 	return a * b + c;
-#endif
+#endif // FP_FAST_FMAF
 }
 
 //! @brief Takes advantage of fma() function if present in hardware
diff --git a/include/versioninfo.h b/include/versioninfo.h
index 2bb74a570..29bf3bea9 100644
--- a/include/versioninfo.h
+++ b/include/versioninfo.h
@@ -1,3 +1,6 @@
+#ifndef VERSION_INFO_H
+#define VERSION_INFO_H
+
 #include "lmms_basics.h"
 
 #ifdef __GNUC__
@@ -47,3 +50,5 @@ constexpr const char* LMMS_BUILDCONF_PLATFORM = "win32";
 #ifdef LMMS_BUILD_HAIKU
 constexpr const char* LMMS_BUILDCONF_PLATFORM = "Haiku";
 #endif
+
+#endif
diff --git a/plugins/Lv2Effect/Lv2Effect.h b/plugins/Lv2Effect/Lv2Effect.h
index 7e1457777..521a7df74 100644
--- a/plugins/Lv2Effect/Lv2Effect.h
+++ b/plugins/Lv2Effect/Lv2Effect.h
@@ -58,4 +58,4 @@ private:
 
 } // namespace lmms
 
-#endif // LMMS_HAVE_LV2
+#endif
diff --git a/plugins/VstBase/RemoteVstPlugin.cpp b/plugins/VstBase/RemoteVstPlugin.cpp
index aaf8aec3d..2b035eca7 100644
--- a/plugins/VstBase/RemoteVstPlugin.cpp
+++ b/plugins/VstBase/RemoteVstPlugin.cpp
@@ -57,7 +57,7 @@
 #include <wine/exception.h>
 #endif
 
-#endif
+#endif // LMMS_BUILD_LINUX
 
 #ifndef NATIVE_LINUX_VST
 #define USE_WS_PREFIX
@@ -883,7 +883,7 @@ void RemoteVstPlugin::initEditor()
 	
 	pluginDispatch(effEditTop);
 	m_x11WindowVisible = true;
-#endif
+#endif // NATIVE_LINUX_VST
 }
 
 
@@ -1090,16 +1090,16 @@ void RemoteVstPlugin::process( const sampleFrame * _in, sampleFrame * _out )
 #ifdef OLD_VST_SDK
 	if( m_plugin->flags & effFlagsCanReplacing )
 	{
-#endif
 		m_plugin->processReplacing( m_plugin, m_inputs, m_outputs,
 								bufferSize() );
-#ifdef OLD_VST_SDK
 	}
 	else
 	{
 		m_plugin->process( m_plugin, m_inputs, m_outputs,
 								bufferSize() );
 	}
+#else
+	m_plugin->processReplacing(m_plugin, m_inputs, m_outputs, bufferSize());
 #endif
 
 	unlockShm();
@@ -1937,7 +1937,7 @@ intptr_t RemoteVstPlugin::hostCallback( AEffect * _effect, int32_t _opcode,
 			// TODO
 			// close window, platform specific handle in <ptr>
 			return 0;
-#endif
+#endif // OLD_VST_SDK
 
 		case audioMasterSizeWindow:
 		{
@@ -2334,7 +2334,7 @@ void RemoteVstPlugin::guiEventLoop()
 		}
 	}
 }
-#endif
+#endif // NATIVE_LINUX_VST
 
 
 #ifndef NATIVE_LINUX_VST
@@ -2385,7 +2385,7 @@ LRESULT CALLBACK RemoteVstPlugin::wndProc( HWND hwnd, UINT uMsg,
 }
 
 
-#endif
+#endif // NATIVE_LINUX_VST
 
 } // namespace lmms
 
@@ -2421,7 +2421,7 @@ int main( int _argc, char * * _argv )
 				sched_get_priority_min( SCHED_FIFO ) ) / 2;
 	sched_setscheduler( 0, SCHED_FIFO, &sparam );
 #endif
-#endif
+#endif // LMMS_BUILD_LINUX
 
 #ifdef LMMS_BUILD_WIN32
 	if( !SetPriorityClass( GetCurrentProcess(), HIGH_PRIORITY_CLASS ) )
diff --git a/plugins/VstBase/VstPlugin.cpp b/plugins/VstBase/VstPlugin.cpp
index bba644305..46d2057dd 100644
--- a/plugins/VstBase/VstPlugin.cpp
+++ b/plugins/VstBase/VstPlugin.cpp
@@ -111,7 +111,7 @@ private:
 	uchar* m_map;
 };
 
-}
+} // namespace PE
 
 namespace lmms
 {
diff --git a/plugins/Xpressive/ExprSynth.cpp b/plugins/Xpressive/ExprSynth.cpp
index e7d7e0951..0a1454345 100644
--- a/plugins/Xpressive/ExprSynth.cpp
+++ b/plugins/Xpressive/ExprSynth.cpp
@@ -363,7 +363,7 @@ namespace SimpleRandom {
 			return dist(generator);
 		}
 	};
-}
+} // namespace SimpleRandom
 
 static freefunc0<float,SimpleRandom::float_random_with_engine,false> simple_rand;
 
diff --git a/plugins/ZynAddSubFx/LocalZynAddSubFx.cpp b/plugins/ZynAddSubFx/LocalZynAddSubFx.cpp
index 2b0c0d974..36f7ce48c 100644
--- a/plugins/ZynAddSubFx/LocalZynAddSubFx.cpp
+++ b/plugins/ZynAddSubFx/LocalZynAddSubFx.cpp
@@ -64,7 +64,7 @@ LocalZynAddSubFx::LocalZynAddSubFx() :
 		pthread_win32_process_attach_np();
 		pthread_win32_thread_attach_np();
 #endif
-#endif
+#endif // LMMS_BUILD_WIN32
 
 		initConfig();
 
diff --git a/plugins/ZynAddSubFx/RemoteZynAddSubFx.cpp b/plugins/ZynAddSubFx/RemoteZynAddSubFx.cpp
index b2e47cade..1de5fb97d 100644
--- a/plugins/ZynAddSubFx/RemoteZynAddSubFx.cpp
+++ b/plugins/ZynAddSubFx/RemoteZynAddSubFx.cpp
@@ -278,7 +278,7 @@ int main( int _argc, char * * _argv )
 	pthread_win32_process_attach_np();
 	pthread_win32_thread_attach_np();
 #endif
-#endif
+#endif // LMMS_BUILD_WIN32
 
 
 #ifdef SYNC_WITH_SHM_FIFO
@@ -298,7 +298,7 @@ int main( int _argc, char * * _argv )
 	pthread_win32_thread_detach_np();
 	pthread_win32_process_detach_np();
 #endif
-#endif
+#endif // LMMS_BUILD_WIN32
 
 	return 0;
 }
diff --git a/src/core/ConfigManager.cpp b/src/core/ConfigManager.cpp
index 59987de97..dbad06784 100644
--- a/src/core/ConfigManager.cpp
+++ b/src/core/ConfigManager.cpp
@@ -566,7 +566,7 @@ void ConfigManager::loadConfigFile(const QString & configFile)
 		}
 #endif
 	}
-#endif
+#endif // LMMS_HAVE_STK
 
 	upgrade();
 
diff --git a/src/core/DrumSynth.cpp b/src/core/DrumSynth.cpp
index 79630e42d..bc5455c96 100644
--- a/src/core/DrumSynth.cpp
+++ b/src/core/DrumSynth.cpp
@@ -37,7 +37,7 @@
 #ifdef _MSC_VER
 //not #if LMMS_BUILD_WIN32 because we have strncasecmp in mingw
 #define strcasecmp _stricmp
-#endif
+#endif // _MSC_VER
 
 namespace lmms
 {
diff --git a/src/core/SampleBuffer.cpp b/src/core/SampleBuffer.cpp
index b931b27b5..68d9af2c9 100644
--- a/src/core/SampleBuffer.cpp
+++ b/src/core/SampleBuffer.cpp
@@ -672,7 +672,7 @@ f_cnt_t SampleBuffer::decodeSampleOGGVorbis(
 
 	return frames;
 }
-#endif
+#endif // LMMS_HAVE_OGGVORBIS
 
 
 
@@ -1258,7 +1258,7 @@ void flacStreamEncoderMetadataCallback(
 	b->write((const char *) metadata, sizeof(*metadata));
 }
 
-#endif
+#endif // LMMS_HAVE_FLAC_STREAM_ENCODER_H
 
 
 
@@ -1314,12 +1314,12 @@ QString & SampleBuffer::toBase64(QString & dst) const
 
 	base64::encode(baWriter.buffer().data(), baWriter.buffer().size(), dst);
 
-#else	/* LMMS_HAVE_FLAC_STREAM_ENCODER_H */
+#else	// LMMS_HAVE_FLAC_STREAM_ENCODER_H
 
 	base64::encode((const char *) m_data,
 		m_frames * sizeof(sampleFrame), dst);
 
-#endif	/* LMMS_HAVE_FLAC_STREAM_ENCODER_H */
+#endif	// LMMS_HAVE_FLAC_STREAM_ENCODER_H
 
 	return dst;
 }
@@ -1461,7 +1461,7 @@ void flacStreamDecoderErrorCallback(
 	// what to do now??
 }
 
-#endif
+#endif // LMMS_HAVE_FLAC_STREAM_DECODER_H
 
 
 void SampleBuffer::loadFromBase64(const QString & data)
@@ -1517,7 +1517,7 @@ void SampleBuffer::loadFromBase64(const QString & data)
 	m_origData = MM_ALLOC<sampleFrame>( m_origFrames);
 	memcpy(m_origData, dst, dsize);
 
-#endif
+#endif // LMMS_HAVE_FLAC_STREAM_DECODER_H
 
 	delete[] dst;
 
diff --git a/src/core/audio/AudioAlsa.cpp b/src/core/audio/AudioAlsa.cpp
index 0cf95f895..1a22413d8 100644
--- a/src/core/audio/AudioAlsa.cpp
+++ b/src/core/audio/AudioAlsa.cpp
@@ -542,4 +542,4 @@ int AudioAlsa::setSWParams()
 
 } // namespace lmms
 
-#endif
+#endif // LMMS_HAVE_ALSA
diff --git a/src/core/audio/AudioFileMP3.cpp b/src/core/audio/AudioFileMP3.cpp
index 75084460f..4930e9ad6 100644
--- a/src/core/audio/AudioFileMP3.cpp
+++ b/src/core/audio/AudioFileMP3.cpp
@@ -134,4 +134,4 @@ void AudioFileMP3::tearDownEncoder()
 
 } // namespace lmms
 
-#endif
+#endif // LMMS_HAVE_MP3LAME
diff --git a/src/core/audio/AudioFileOgg.cpp b/src/core/audio/AudioFileOgg.cpp
index 1f40f456e..d61e27da8 100644
--- a/src/core/audio/AudioFileOgg.cpp
+++ b/src/core/audio/AudioFileOgg.cpp
@@ -272,6 +272,6 @@ void AudioFileOgg::finishEncoding()
 
 } // namespace lmms
 
-#endif
+#endif // LMMS_HAVE_OGGVORBIS
 
 
diff --git a/src/core/audio/AudioJack.cpp b/src/core/audio/AudioJack.cpp
index 071a6e3c3..daf5bbd10 100644
--- a/src/core/audio/AudioJack.cpp
+++ b/src/core/audio/AudioJack.cpp
@@ -339,7 +339,7 @@ void AudioJack::renamePort( AudioPort * _port )
 #endif
 		}
 	}
-#endif
+#endif // AUDIO_PORT_SUPPORT
 }
 
 
@@ -502,4 +502,4 @@ void AudioJack::setupWidget::saveSettings()
 
 } // namespace lmms
 
-#endif
+#endif // LMMS_HAVE_JACK
diff --git a/src/core/audio/AudioOss.cpp b/src/core/audio/AudioOss.cpp
index 4480e399c..d79ed939d 100644
--- a/src/core/audio/AudioOss.cpp
+++ b/src/core/audio/AudioOss.cpp
@@ -362,5 +362,5 @@ void AudioOss::setupWidget::saveSettings()
 
 } // namespace lmms
 
-#endif
+#endif // LMMS_HAVE_OSS
 
diff --git a/src/core/audio/AudioPortAudio.cpp b/src/core/audio/AudioPortAudio.cpp
index b1e9cb5c4..03bceaa89 100644
--- a/src/core/audio/AudioPortAudio.cpp
+++ b/src/core/audio/AudioPortAudio.cpp
@@ -511,7 +511,7 @@ void AudioPortAudio::setupWidget::show()
 } // namespace lmms
 
 
-#endif
+#endif // LMMS_HAVE_PORTAUDIO
 
 
 
diff --git a/src/core/audio/AudioPulseAudio.cpp b/src/core/audio/AudioPulseAudio.cpp
index 40c955434..d1476f836 100644
--- a/src/core/audio/AudioPulseAudio.cpp
+++ b/src/core/audio/AudioPulseAudio.cpp
@@ -353,5 +353,5 @@ void AudioPulseAudio::setupWidget::saveSettings()
 
 } // namespace lmms
 
-#endif
+#endif // LMMS_HAVE_PULSEAUDIO
 
diff --git a/src/core/audio/AudioSdl.cpp b/src/core/audio/AudioSdl.cpp
index d321e8566..8d4687518 100644
--- a/src/core/audio/AudioSdl.cpp
+++ b/src/core/audio/AudioSdl.cpp
@@ -304,7 +304,7 @@ void AudioSdl::sdlAudioCallback( Uint8 * _buf, int _len )
 		m_convertedBufPos += min_len;
 		m_convertedBufPos %= m_convertedBufSize;
 	}
-#endif
+#endif // LMMS_HAVE_SDL2
 }
 
 #ifdef LMMS_HAVE_SDL2
@@ -349,5 +349,5 @@ void AudioSdl::setupWidget::saveSettings()
 
 } // namespace lmms
 
-#endif
+#endif // LMMS_HAVE_SDL
 
diff --git a/src/core/audio/AudioSndio.cpp b/src/core/audio/AudioSndio.cpp
index 0ba801585..a8ea34ce1 100644
--- a/src/core/audio/AudioSndio.cpp
+++ b/src/core/audio/AudioSndio.cpp
@@ -215,4 +215,4 @@ void AudioSndio::setupWidget::saveSettings()
 
 } // namespace lmms
 
-#endif	/* LMMS_HAVE_SNDIO */
+#endif	// LMMS_HAVE_SNDIO
diff --git a/src/core/audio/AudioSoundIo.cpp b/src/core/audio/AudioSoundIo.cpp
index 4d8c48708..633808204 100644
--- a/src/core/audio/AudioSoundIo.cpp
+++ b/src/core/audio/AudioSoundIo.cpp
@@ -521,4 +521,4 @@ void AudioSoundIo::setupWidget::saveSettings()
 
 } // namespace lmms
 
-#endif
+#endif // LMMS_HAVE_SOUNDIO
diff --git a/src/core/main.cpp b/src/core/main.cpp
index 43e744e5b..58758c2b1 100644
--- a/src/core/main.cpp
+++ b/src/core/main.cpp
@@ -120,7 +120,7 @@ void consoleMessageHandler(QtMsgType type,
     QByteArray localMsg = msg.toLocal8Bit();
     fprintf(stderr, "%s\n", localMsg.constData());
 }
-#endif
+#endif // LMMS_BUILD_WIN32
 
 
 inline void loadTranslation( const QString & tname,
@@ -776,7 +776,7 @@ int main( int argc, char * * argv )
 		printf( "Notice: could not set realtime priority.\n" );
 	}
 #endif
-#endif
+#endif // LMMS_HAVE_SCHED_H
 #endif
 
 #ifdef LMMS_BUILD_WIN32
diff --git a/src/core/midi/MidiSndio.cpp b/src/core/midi/MidiSndio.cpp
index e7f2362f6..e644113b2 100644
--- a/src/core/midi/MidiSndio.cpp
+++ b/src/core/midi/MidiSndio.cpp
@@ -118,4 +118,4 @@ void MidiSndio::run()
 
 } // namespace lmms
 
-#endif	/* LMMS_HAVE_SNDIO */
+#endif	// LMMS_HAVE_SNDIO
diff --git a/src/gui/AudioAlsaSetupWidget.cpp b/src/gui/AudioAlsaSetupWidget.cpp
index f6e91f8e3..8a253c75a 100644
--- a/src/gui/AudioAlsaSetupWidget.cpp
+++ b/src/gui/AudioAlsaSetupWidget.cpp
@@ -120,4 +120,4 @@ void AudioAlsaSetupWidget::onCurrentIndexChanged(int index)
 
 } // namespace lmms::gui
 
-#endif
+#endif // LMMS_HAVE_ALSA
diff --git a/src/gui/MainApplication.cpp b/src/gui/MainApplication.cpp
index a08df0f09..af8a71684 100644
--- a/src/gui/MainApplication.cpp
+++ b/src/gui/MainApplication.cpp
@@ -105,7 +105,7 @@ bool MainApplication::nativeEventFilter(const QByteArray& eventType,
 	}
 	return false;
 }
-#endif
+#endif // LMMS_BUILD_WIN32
 
 
 } // namespace lmms::gui
diff --git a/src/gui/MixerView.cpp b/src/gui/MixerView.cpp
index 32355edd6..9103a5584 100644
--- a/src/gui/MixerView.cpp
+++ b/src/gui/MixerView.cpp
@@ -624,4 +624,4 @@ void MixerView::updateFaders()
 }
 
 
-} // namesapce lmms::gui
+} // namespace lmms::gui
diff --git a/src/gui/instrument/PianoView.cpp b/src/gui/instrument/PianoView.cpp
index b6dec8b4f..87a356afc 100644
--- a/src/gui/instrument/PianoView.cpp
+++ b/src/gui/instrument/PianoView.cpp
@@ -211,7 +211,7 @@ int PianoView::getKeyFromKeyEvent( QKeyEvent * _ke )
 		case 13: return 30; // =
 		case 27: return 31; // ]
 	}
-#endif
+#endif // LMMS_BUILD_WIN32
 #if defined(LMMS_BUILD_LINUX) || defined(LMMS_BUILD_OPENBSD) || defined(LMMS_BUILD_FREEBSD)
 	switch( k )
 	{
@@ -292,7 +292,7 @@ int PianoView::getKeyFromKeyEvent( QKeyEvent * _ke )
 		case 29: return 27; // 0 = d'#
 		case 35: return 28; // P = e'
 	}
-#endif
+#endif // LMMS_BUILD_APPLE
 
 	return -100;
 }
diff --git a/tests/scripted/check-namespace b/tests/scripted/check-namespace
new file mode 100755
index 000000000..8c1b405ad
--- /dev/null
+++ b/tests/scripted/check-namespace
@@ -0,0 +1,195 @@
+#!/usr/bin/python3
+
+# This script checks the code for namespace related issues
+# Note: This script is not perfect. It can not parse all LMMS files,
+#       and does not contain a complete C++ parser. If you encounter
+#       difficulties with this tests, it could be a fault of your
+#       changes, but it could also be a fault of this script.
+
+import re
+import subprocess
+import sys
+from pathlib import Path
+from typing import NamedTuple
+
+
+# types
+
+class BlockType:
+    pass
+
+
+IF_MACRO = BlockType()
+HEADER_GUARD = BlockType()
+CODE_BLOCK = BlockType()
+EXTERN = BlockType()
+
+
+class Expectation(NamedTuple):
+    type: BlockType
+    statement: str  # expected end statement
+    name: str  # expected name in comment
+
+
+# global variables
+
+errors = 0
+
+
+# functions
+
+def caption(my_str):
+    print(f'\n# {my_str}\n')
+
+
+def error(where, match, my_str):
+    global errors
+    errors += 1
+    if match:
+        line = match.string[:match.start()].count('\n') + 1  # first line is 1
+        where = f'{where}:{line}'
+    print(f'Error: {where}: {my_str}')
+
+
+if not Path('.gitmodules').is_file():
+    print('You need to call this script from the LMMS top directory')
+    exit(1)
+
+result = subprocess.run(['git', 'ls-files', '*.[ch]', '*.[ch]pp', ':!tests/*'],
+                        capture_output=True, text=True, check=True)
+
+known_no_namespace_lmms = {
+    # main.cpp
+    'src/core/main.cpp',
+    # nothing to set under a namespace
+    'include/debug.h',
+    'include/versioninfo.h',
+    'plugins/CarlaBase/CarlaConfig/config.h',
+    'plugins/CarlaBase/DummyCarla.cpp',
+    # unclear why it has no namespace
+    'plugins/ZynAddSubFx/RemoteZynAddSubFx.cpp',
+}
+
+exclude_files = re.compile(
+    # not ours:
+    'include/(aeffectx|fenv|ladspa).h|'
+    'plugins/LadspaEffect/(calf|caps|cmt|swh|tap)/|'
+    'plugins/MidiExport/MidiFile.hpp|'
+    'plugins/ReverbSC/[a-z]|'
+    'plugins/Sf2Player/fluidsynthshims.h|'
+    '/portsmf/'
+)
+
+files = [Path(f) for f in result.stdout.splitlines() if not exclude_files.search(f)]
+
+# Debug argument
+if len(sys.argv) > 1:
+    files = [Path(arg) for arg in sys.argv[1:]]
+
+statement_pattern = re.compile(
+    # Capture comments first to prevent them from matching any other regex
+    #  Include next line if line ends with backslash
+    r'/[*](.|\n)*?[*]/|//(.*\\\n)*.*|'
+
+    # Macro with <30 lines and no other #if inside needs no end comment
+    #  Match here to prevent from matching next regex
+    #  With a (?!negative lookahead) we can allow all # except the ones followed by "if"
+    r'^ *# *(?P<short_macro>ifn?def)(?=(([^#\n]|#(?!if|endif))*\n){,30} *# *endif)|'
+    # Macro followed by name or comment
+    #  With (?P<name>...) you can do a backreference to \name later
+    r'^ *# *(?P<named_macro>ifn?def|endif)(( *// *| +)(?P<macro_name>\w+))?|'
+    # Other macros where we don't want the argument
+    r'^ *# *(?P<macro>include|if|el(se|if))|'
+
+    # Namespace that contains no other braces needs no end comment
+    #  With a (?=lookahead) we can let the "namespace" part be eaten by the parser
+    #  but save the braces and their content for later so they can be matched again
+    r'^ *namespace *[\w:]*\s*(?={[^{}]*})|'
+    # Start of named namespace, extern "C" or just a opening brace
+    r'(^ *(namespace +(?P<namespace>[\w:]+)|(?P<extern>extern *"C"))\s*)?(?P<opening_brace>{)|'
+    # End of namespace including comment, or just a closing brace
+    r'(?P<closing_brace>})( *// *namespace +(?P<namespace_end>[\w:]+))?'
+
+    # In all the regexes above match both tab and space when a space is used
+    r''.replace(' ', r'[\t ]'),
+    # Make ^ match on every line, not just beginning of file
+    re.MULTILINE)
+
+# Comments and whitespace followed by header guard
+header_guard_pattern = re.compile(r'^(/[*](.|\n)*?[*]/|//.*|\s)*#\s*(ifndef|pragma\s+once)')
+
+# Namespace lmms
+namespace_pattern = re.compile(r'^\s*namespace\s+lmms', re.MULTILINE)
+
+#
+# the real code
+#
+
+caption('namespace checks')
+
+for cur_file in files:
+    if cur_file.is_file():
+        cur_text = cur_file.read_text(errors='replace')
+
+        if str(cur_file) not in known_no_namespace_lmms:
+            namespace_pattern.search(cur_text) or error(cur_file, None, f'File has no namespace lmms')
+
+        header_guard = str(cur_file).endswith('.h')
+        expectations = []  # type: list[Expectation]
+
+        if header_guard:
+            if not header_guard_pattern.match(cur_text):
+                error(cur_file, None, 'First statement should be header guard')
+                header_guard = False
+
+        for m in statement_pattern.finditer(cur_text):
+            # Find the matched regex group
+            statement = m.group('opening_brace') or m.group('closing_brace')
+            if not statement:
+                statement = '#' + (m.group('macro') or m.group('named_macro') or m.group('short_macro') or '')
+            if not statement:
+                continue
+
+            # Start statements
+            if statement == '{':
+                etype = EXTERN if m.group('extern') else CODE_BLOCK
+                expectations.append(Expectation(etype, '}', m.group('namespace')))
+            elif statement.startswith('#if'):
+                etype = HEADER_GUARD if header_guard else IF_MACRO
+                expectations.append(Expectation(etype, '#endif', m.group('macro_name')))
+                header_guard = False
+
+            # End statements
+            elif statement == '#endif' or statement.startswith('#el') or statement == '}':
+                if not expectations:
+                    error(cur_file, m, f'Unexpected {statement}')
+                    break
+                # Don't pop the expectation for an #else tag, we are still waiting for the #endif
+                if statement.startswith('#el') and expectations[-1].statement == '#endif':
+                    continue
+                exp = expectations.pop()
+                name = m.group('macro_name') or m.group('namespace_end') or ''
+                if statement != exp.statement:
+                    error(cur_file, m, f'Expected {exp.statement} before {statement}')
+                    break
+                # Require no end comment for header guard
+                elif exp.type is HEADER_GUARD and not name:
+                    continue
+                elif exp.name and name != exp.name:
+                    comment = 'namespace ' if exp.type is CODE_BLOCK else ''
+                    error(cur_file, m, f'Missing comment // {comment}{exp.name}')
+
+            # Extra checks
+            elif statement == '#include':
+                if any(True for e in expectations if e.type is CODE_BLOCK):
+                    error(cur_file, m, '#include inside a code block')
+
+        else:
+            # Leftover expected statements
+            for exp in reversed(expectations):
+                error(cur_file, None, f'Expected {exp.statement} before end of file')
+
+caption('summary')
+
+print(f'{str(errors)} errors.')
+exit(1 if errors > 0 else 0)
diff --git a/tests/scripted/verify b/tests/scripted/verify
index 5c27ef898..20a26a303 100755
--- a/tests/scripted/verify
+++ b/tests/scripted/verify
@@ -81,6 +81,7 @@ lmms_main_path = Path(__file__).resolve().parent.parent.parent
 with tempfile.TemporaryDirectory() as tmpdir:
 	os.chdir(tmpdir)
 	check_strings = lmms_main_path / 'tests' / 'scripted' / 'check-strings'
+	check_namespace = lmms_main_path / 'tests' / 'scripted' / 'check-namespace'
 
 	# create dummy carla repo
 	Path('carla').mkdir()
@@ -158,5 +159,92 @@ with tempfile.TemporaryDirectory() as tmpdir:
 		test.expect('Error: debian/copyright: Glob/Path does not exist: NonExistent')
 		test.expect('1 errors')
 
+	with ScriptTest(check_namespace) as test:
+		# minimal working example
+		test.run(0)  # exitcode 0 - no errors expected
+		test.expect('0 errors')
+
+		create_file('01_OddBraceWithinMacro.cpp', '''
+					#if HAS_EVEN_BRACES
+						namespace lmms {}
+					#endif
+					namespace lmms {
+					#if HAS_ODD_BRACE
+					}
+					#endif
+					''')
+		create_file('02_IncludeInCodeBlock.cpp', '''
+					#include <good>
+					extern "C" {
+						#include "alright.c"
+					}
+					namespace lmms {
+						#include <bad>
+					}
+					''')
+		create_file('03_MacroComments.h', '''
+					#ifndef HEADER_GUARD_NEEDS_NO_COMMENT
+					#define HEADER_GUARD_NEEDS_NO_COMMENT
+						#ifdef HAS_NESTED_NEEDS_COMMENT
+							#ifdef SHORT_NO_NESTED_NEEDS_NO_COMMENT
+								namespace lmms {}
+							#endif
+						#endif
+						#ifdef HAS_COMMENT
+							#ifdef SHORT_NO_NESTED_NEEDS_NO_COMMENT
+							#else
+							#endif
+						#endif // HAS_COMMENT
+					#endif
+					''')
+		create_file('04_NamespaceComments.cpp', '''
+					namespace lmms {
+						namespace ShortNamespace {
+							class WithDeclarationsOnly;
+						}
+						namespace LongNamespace {
+							class WithDefinition {
+								int x;
+							};
+						}
+					} // namespace lmms
+					''')
+		create_file('05_NoHeaderGuard.h', '''
+					#include <cstdio>
+					namespace lmms {}
+					''')
+		create_file('06_PragmaButNoLmms.h', '''
+					// should not cause header guard warning
+					#pragma once
+					namespace not_lmms {}
+					''')
+		create_file('07_MismatchingEndifName.h', '''
+					#ifndef ABC_H
+					namespace lmms {
+					\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
+					}
+					#endif // XYZ_H
+					''')
+		create_file('08_MismatchingNamespaceEndName.h', '''
+					#ifndef ABC_H
+					namespace lmms {
+					{}
+					} // namespace smml
+					#endif // ABC_H
+					''')
+		test.run()
+		test.expect('8 errors')
+		test.expect('''
+Error: 01_OddBraceWithinMacro.cpp:7: Expected #endif before }
+Error: 02_IncludeInCodeBlock.cpp:7: #include inside a code block
+Error: 03_MacroComments.h:8: Missing comment // HAS_NESTED_NEEDS_COMMENT
+Error: 04_NamespaceComments.cpp:10: Missing comment // namespace LongNamespace
+Error: 05_NoHeaderGuard.h: First statement should be header guard
+Error: 06_PragmaButNoLmms.h: File has no namespace lmms
+Error: 07_MismatchingEndifName.h:36: Missing comment // ABC_H
+Error: 08_MismatchingNamespaceEndName.h:5: Missing comment // namespace lmms
+''')
+
+
 # if we made it until here without an exception, all tests have been passed
 print("SUCCESS")