diff --git a/source/backend/CarlaBackend.h b/source/backend/CarlaBackend.h
index 33d9a51c4..ba0c66260 100644
--- a/source/backend/CarlaBackend.h
+++ b/source/backend/CarlaBackend.h
@@ -210,6 +210,11 @@ static constexpr const uint PLUGIN_HAS_CUSTOM_UI_USING_FILE_OPEN = 0x2000;
  */
 static constexpr const uint PLUGIN_NEEDS_MAIN_THREAD_IDLE = 0x4000;
 
+/*!
+ * Plugin has its own custom UI which is user resizable.
+ */
+static constexpr const uint PLUGIN_HAS_CUSTOM_RESIZABLE_UI = 0x8000;
+
 /** @} */
 
 /* ------------------------------------------------------------------------------------------------------------
diff --git a/source/backend/plugin/CarlaPluginBridge.cpp b/source/backend/plugin/CarlaPluginBridge.cpp
index 5b29acd42..c206a54cc 100644
--- a/source/backend/plugin/CarlaPluginBridge.cpp
+++ b/source/backend/plugin/CarlaPluginBridge.cpp
@@ -2193,7 +2193,7 @@ public:
                 if (fBridgeVersion < 9 || fBinaryType == BINARY_WIN32 || fBinaryType == BINARY_WIN64)
                #endif
                 {
-                    pData->hints &= ~PLUGIN_HAS_CUSTOM_EMBED_UI;
+                    pData->hints &= ~(PLUGIN_HAS_CUSTOM_EMBED_UI|PLUGIN_HAS_CUSTOM_RESIZABLE_UI);
                 }
 
                 fInfo.category = static_cast<PluginCategory>(category);
diff --git a/source/backend/plugin/CarlaPluginCLAP.cpp b/source/backend/plugin/CarlaPluginCLAP.cpp
index 43b7de9a2..c01bb62b8 100644
--- a/source/backend/plugin/CarlaPluginCLAP.cpp
+++ b/source/backend/plugin/CarlaPluginCLAP.cpp
@@ -1811,6 +1811,8 @@ public:
                 pData->hints |= PLUGIN_HAS_CUSTOM_UI;
                 pData->hints |= PLUGIN_HAS_CUSTOM_EMBED_UI;
                 pData->hints |= PLUGIN_NEEDS_UI_MAIN_THREAD;
+                if (guiExt->can_resize(fPlugin))
+                    pData->hints |= PLUGIN_HAS_CUSTOM_RESIZABLE_UI;
             }
             else if (guiExt->is_api_supported(fPlugin, CLAP_WINDOW_API_NATIVE, true))
             {
diff --git a/source/backend/plugin/CarlaPluginLV2.cpp b/source/backend/plugin/CarlaPluginLV2.cpp
index 2ecfc1130..001abc252 100644
--- a/source/backend/plugin/CarlaPluginLV2.cpp
+++ b/source/backend/plugin/CarlaPluginLV2.cpp
@@ -3315,7 +3315,18 @@ public:
                 case LV2_UI_OLD_EXTERNAL:
                     break;
                 default:
-                    pData->hints |= PLUGIN_HAS_CUSTOM_EMBED_UI;
+                    pData->hints |= PLUGIN_HAS_CUSTOM_EMBED_UI|PLUGIN_HAS_CUSTOM_RESIZABLE_UI;
+                    for (uint32_t i = 0; i < fUI.rdfDescriptor->ExtensionCount; ++i)
+                    {
+                        const char* const extension = fUI.rdfDescriptor->Extensions[i];
+                        CARLA_SAFE_ASSERT_CONTINUE(extension != nullptr);
+
+                        if (std::strcmp(extension, LV2_UI__noUserResize) == 0)
+                        {
+                            pData->hints &= ~PLUGIN_HAS_CUSTOM_RESIZABLE_UI;
+                            break;
+                        }
+                    }
                     break;
                 }
             }
diff --git a/source/backend/plugin/CarlaPluginVST3.cpp b/source/backend/plugin/CarlaPluginVST3.cpp
index b5e4643d5..0e7f16b26 100644
--- a/source/backend/plugin/CarlaPluginVST3.cpp
+++ b/source/backend/plugin/CarlaPluginVST3.cpp
@@ -2319,6 +2319,8 @@ public:
             pData->hints |= PLUGIN_HAS_CUSTOM_UI;
             pData->hints |= PLUGIN_HAS_CUSTOM_EMBED_UI;
             pData->hints |= PLUGIN_NEEDS_UI_MAIN_THREAD;
+            if (v3_cpp_obj(fV3.view)->can_resize(fV3.view) == V3_TRUE)
+                pData->hints |= PLUGIN_HAS_CUSTOM_RESIZABLE_UI;
         }
        #endif
 
diff --git a/source/backend/utils/CachedPlugins.cpp b/source/backend/utils/CachedPlugins.cpp
index 6ad7abc03..bec3462a7 100644
--- a/source/backend/utils/CachedPlugins.cpp
+++ b/source/backend/utils/CachedPlugins.cpp
@@ -262,15 +262,26 @@ static const CarlaCachedPluginInfo* get_cached_plugin_lv2(Lv2WorldClass& lv2Worl
                 if (false)
                #endif
                 {
-                    info.hints |= CB::PLUGIN_HAS_CUSTOM_EMBED_UI;
+                    info.hints |= CB::PLUGIN_HAS_CUSTOM_EMBED_UI|CB::PLUGIN_HAS_CUSTOM_RESIZABLE_UI;
+
+                    Lilv::Nodes lilvSupportedFeatureNodes(lilvUI.get_supported_features());
+                    LILV_FOREACH(nodes, it, lilvSupportedFeatureNodes)
+                    {
+                        Lilv::Node lilvFeatureNode(lilvSupportedFeatureNodes.get(it));
+                        const char* const featureURI(lilvFeatureNode.as_uri());
+                        CARLA_SAFE_ASSERT_CONTINUE(featureURI != nullptr);
+
+                        if (std::strcmp(featureURI, LV2_UI__noUserResize) == 0)
+                        {
+                            info.hints &= ~CB::PLUGIN_HAS_CUSTOM_RESIZABLE_UI;
+                            break;
+                        }
+                    }
+                    lilv_nodes_free(const_cast<LilvNodes*>(lilvSupportedFeatureNodes.me));
                     break;
                 }
             }
         }
-#ifdef CARLA_OS_LINUX
-        else if (lilvPlugin.get_modgui_resources_directory().as_uri() != nullptr)
-            info.hints |= CB::PLUGIN_HAS_CUSTOM_UI;
-#endif
 
         lilv_nodes_free(const_cast<LilvNodes*>(lilvUIs.me));
     }
diff --git a/source/discovery/carla-discovery.cpp b/source/discovery/carla-discovery.cpp
index ed2b16ec1..3d40a0ab7 100644
--- a/source/discovery/carla-discovery.cpp
+++ b/source/discovery/carla-discovery.cpp
@@ -1824,9 +1824,9 @@ static bool do_vst3_check(lib_t& libHandle, const char* const filename, const bo
             if (v3_cpp_obj(view)->is_platform_type_supported(view, V3_VIEW_PLATFORM_TYPE_NATIVE) == V3_TRUE)
             {
                 hints |= PLUGIN_HAS_CUSTOM_UI;
-               #ifndef BUILD_BRIDGE
                 hints |= PLUGIN_HAS_CUSTOM_EMBED_UI;
-               #endif
+                if (v3_cpp_obj(view)->can_resize(view) == V3_TRUE)
+                    hints |= PLUGIN_HAS_CUSTOM_RESIZABLE_UI;
             }
 
             v3_cpp_obj_unref(view);
@@ -2634,10 +2634,12 @@ static bool do_clap_check(lib_t& libHandle, const char* const filename, const bo
             if (gui != nullptr)
             {
                 hints |= PLUGIN_HAS_CUSTOM_UI;
-               #ifndef BUILD_BRIDGE
                 if (gui->is_api_supported(plugin, CLAP_WINDOW_API_NATIVE, false))
+                {
                     hints |= PLUGIN_HAS_CUSTOM_EMBED_UI;
-               #endif
+                    if (gui->can_resize(plugin))
+                        hints |= PLUGIN_HAS_CUSTOM_RESIZABLE_UI;
+                }
             }
            #endif
 
diff --git a/source/frontend/carla_backend.py b/source/frontend/carla_backend.py
index 49c41f2ae..15b93a158 100644
--- a/source/frontend/carla_backend.py
+++ b/source/frontend/carla_backend.py
@@ -207,6 +207,21 @@ PLUGIN_USES_MULTI_PROGS = 0x400
 # Plugin can make use of inline display API.
 PLUGIN_HAS_INLINE_DISPLAY = 0x800
 
+# Plugin has its own custom UI which can be embed into another Window.
+# @see carla_embed_custom_ui()
+# @note This is very experimental and subject to change at this point
+PLUGIN_HAS_CUSTOM_EMBED_UI = 0x1000
+
+# Plugin custom UI is a fake one that simply invokes an open file browser dialog.
+PLUGIN_HAS_CUSTOM_UI_USING_FILE_OPEN = 0x2000
+
+# Plugin needs all idle events in the main thread.
+# @note Not possible on all engine implementations.
+PLUGIN_NEEDS_MAIN_THREAD_IDLE = 0x4000
+
+# Plugin has its own custom UI which is user resizable.
+PLUGIN_HAS_CUSTOM_RESIZABLE_UI = 0x8000
+
 # ---------------------------------------------------------------------------------------------------------------------
 # Plugin Options
 # Various plugin options.