diff --git a/dgl/Application.hpp b/dgl/Application.hpp
index 2c166b8e..3bac2f8a 100644
--- a/dgl/Application.hpp
+++ b/dgl/Application.hpp
@@ -84,6 +84,17 @@ public:
     */
     void removeIdleCallback(IdleCallback* callback);
 
+   /**
+      Set the class name of the application.
+
+      This is a stable identifier for the application, used as the window class/instance name on X11 and Windows.
+      It is not displayed to the user, but can be used in scripts and by window managers,
+      so it should be the same for every instance of the application, but different from other applications.
+
+      Plugins created with DPF have their class name automatically set based on DGL_NAMESPACE and plugin name.
+    */
+    void setClassName(const char* name);
+
 private:
     struct PrivateData;
     PrivateData* const pData;
diff --git a/dgl/src/Application.cpp b/dgl/src/Application.cpp
index cd6e8a34..80d5957c 100644
--- a/dgl/src/Application.cpp
+++ b/dgl/src/Application.cpp
@@ -67,6 +67,11 @@ void Application::removeIdleCallback(IdleCallback* const callback)
     pData->idleCallbacks.remove(callback);
 }
 
+void Application::setClassName(const char* const name)
+{
+    pData->setClassName(name);
+}
+
 // --------------------------------------------------------------------------------------------------------------------
 
 END_NAMESPACE_DGL
diff --git a/dgl/src/ApplicationPrivateData.cpp b/dgl/src/ApplicationPrivateData.cpp
index 07cb21fb..409085b2 100644
--- a/dgl/src/ApplicationPrivateData.cpp
+++ b/dgl/src/ApplicationPrivateData.cpp
@@ -41,18 +41,7 @@ Application::PrivateData::PrivateData(const bool standalone)
     DISTRHO_SAFE_ASSERT_RETURN(world != nullptr,);
 
     puglSetWorldHandle(world, this);
-
-    // FIXME
-    static int wc_count = 0;
-    char classNameBuf[256];
-    std::srand((std::time(NULL)));
-    std::snprintf(classNameBuf, sizeof(classNameBuf), "%s_%d-%d-%p",
-                  "TESTING", std::rand(), ++wc_count, this);
-    // DISTRHO_MACRO_AS_STRING(DGL_NAMESPACE)
-    classNameBuf[sizeof(classNameBuf)-1] = '\0';
-    d_stderr("--------------------------------------------------------------- className is %s", classNameBuf);
-
-    puglSetClassName(world, classNameBuf);
+    puglSetClassName(world, DISTRHO_MACRO_AS_STRING(DGL_NAMESPACE));
 #ifdef HAVE_X11
     sofdFileDialogSetup(world);
 #endif
@@ -136,6 +125,13 @@ void Application::PrivateData::quit()
 #endif
 }
 
+void Application::PrivateData::setClassName(const char* const name)
+{
+    DISTRHO_SAFE_ASSERT_RETURN(name != nullptr && name[0] != '\0',);
+
+    puglSetClassName(world, name);
+}
+
 // --------------------------------------------------------------------------------------------------------------------
 
 END_NAMESPACE_DGL
diff --git a/dgl/src/ApplicationPrivateData.hpp b/dgl/src/ApplicationPrivateData.hpp
index 4841c969..627f2a1f 100644
--- a/dgl/src/ApplicationPrivateData.hpp
+++ b/dgl/src/ApplicationPrivateData.hpp
@@ -76,6 +76,9 @@ struct Application::PrivateData {
         For standalone mode only. */
     void quit();
 
+    /** Set pugl world class name. */
+    void setClassName(const char* name);
+
     DISTRHO_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(PrivateData)
 };
 
diff --git a/distrho/src/DistrhoUIInternal.hpp b/distrho/src/DistrhoUIInternal.hpp
index d628c619..21a0625e 100644
--- a/distrho/src/DistrhoUIInternal.hpp
+++ b/distrho/src/DistrhoUIInternal.hpp
@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2020 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any purpose with
  * or without fee is hereby granted, provided that the above copyright notice and this
@@ -53,14 +53,35 @@ UI* createUiWrapper(void* dspPtr, uintptr_t winId, double scaleFactor, const cha
 UI* createUiWrapper(void* dspPtr, Window* window);
 #endif
 
+#if !DISTRHO_PLUGIN_HAS_EXTERNAL_UI
+// -----------------------------------------------------------------------
+// Plugin Application, will set class name based on plugin details
+
+class PluginApplication : public Application
+{
+public:
+    PluginApplication()
+      : Application(DISTRHO_UI_IS_STANDALONE)
+    {
+        const char* const className = (
+#ifdef DISTRHO_PLUGIN_BRAND
+            DISTRHO_PLUGIN_BRAND
+#else
+            DISTRHO_MACRO_AS_STRING(DISTRHO_NAMESPACE)
+#endif
+            "-" DISTRHO_PLUGIN_NAME
+        );
+        setClassName(className);
+    }
+};
+
 // -----------------------------------------------------------------------
 // Plugin Window, needed to take care of resize properly
 
-#if !DISTRHO_PLUGIN_HAS_EXTERNAL_UI
 class UIExporterWindow : public Window
 {
 public:
-    UIExporterWindow(Application& app, const intptr_t winId, const double scaleFactor, void* const dspPtr)
+    UIExporterWindow(PluginApplication& app, const intptr_t winId, const double scaleFactor, void* const dspPtr)
         : Window(app, winId, scaleFactor, DISTRHO_UI_USER_RESIZABLE),
           fUI(createUiWrapper(dspPtr, this)),
           fIsReady(false)
@@ -143,7 +164,7 @@ public:
 #if DISTRHO_PLUGIN_HAS_EXTERNAL_UI
         : fUI(createUiWrapper(dspPtr, winId, scaleFactor, bundlePath)),
 #else
-        : glApp(DISTRHO_UI_IS_STANDALONE),
+        : glApp(),
           glWindow(glApp, winId, scaleFactor, dspPtr),
           fChangingSize(false),
           fUI(glWindow.getUI()),
@@ -461,8 +482,8 @@ private:
     // -------------------------------------------------------------------
     // DGL Application and Window for this widget
 
-    Application      glApp;
-    UIExporterWindow glWindow;
+    PluginApplication glApp;
+    UIExporterWindow  glWindow;
 
     // prevent recursion
     bool fChangingSize;