diff --git a/dgl/Window.hpp b/dgl/Window.hpp
index c2046153..181f0122 100644
--- a/dgl/Window.hpp
+++ b/dgl/Window.hpp
@@ -397,10 +397,10 @@ public:
     void runAsModal(bool blockWait = false);
 
    /**
-      Get the size constraint set for the Window.
+      Get the geometry constraints set for the Window.
       @see setGeometryConstraints
     */
-    Size<uint> getMinimumSizeConstraint(bool& keepAspectRatio);
+    Size<uint> getGeometryConstraints(bool& keepAspectRatio);
 
    /**
       Set geometry constraints for the Window when resized by the user, and optionally scale contents automatically.
diff --git a/dgl/src/Window.cpp b/dgl/src/Window.cpp
index 776db8d6..c09106fa 100644
--- a/dgl/src/Window.cpp
+++ b/dgl/src/Window.cpp
@@ -346,7 +346,7 @@ void Window::runAsModal(bool blockWait)
     pData->runAsModal(blockWait);
 }
 
-Size<uint> Window::getMinimumSizeConstraint(bool& keepAspectRatio)
+Size<uint> Window::getGeometryConstraints(bool& keepAspectRatio)
 {
     keepAspectRatio = pData->keepAspectRatio;
     return Size<uint>(pData->minWidth, pData->minHeight);
diff --git a/distrho/extra/ExternalWindow.hpp b/distrho/extra/ExternalWindow.hpp
index 53b0f541..1f1c360b 100644
--- a/distrho/extra/ExternalWindow.hpp
+++ b/distrho/extra/ExternalWindow.hpp
@@ -295,7 +295,8 @@ public:
     */
     void setSize(uint width, uint height)
     {
-        DISTRHO_SAFE_ASSERT_UINT2_RETURN(width > 1 && height > 1, width, height,);
+        DISTRHO_SAFE_ASSERT_UINT_RETURN(width > 1, width,);
+        DISTRHO_SAFE_ASSERT_UINT_RETURN(height > 1, height,);
 
         if (pData.width == width && pData.height == height)
             return;
@@ -314,10 +315,24 @@ public:
     {
         if (pData.title == title)
             return;
+
         pData.title = title;
         titleChanged(title);
     }
 
+   /**
+      Set geometry constraints for the Window when resized by the user.
+    */
+    void setGeometryConstraints(uint minimumWidth, uint minimumHeight, bool keepAspectRatio = false)
+    {
+        DISTRHO_SAFE_ASSERT_UINT_RETURN(minimumWidth > 0, minimumWidth,);
+        DISTRHO_SAFE_ASSERT_UINT_RETURN(minimumHeight > 0, minimumHeight,);
+
+        pData.minWidth = minimumWidth;
+        pData.minHeight = minimumHeight;
+        pData.keepAspectRatio = keepAspectRatio;
+    }
+
    /* --------------------------------------------------------------------------------------------------------
     * TopLevelWidget-like calls - actions called by the host */
 
@@ -339,6 +354,7 @@ public:
     {
         if (pData.visible == visible)
             return;
+
         pData.visible = visible;
         visibilityChanged(visible);
     }
@@ -351,6 +367,7 @@ public:
     {
         if (pData.transientWinId == winId)
             return;
+
         pData.transientWinId = winId;
         transientParentWindowChanged(winId);
     }
@@ -388,39 +405,35 @@ protected:
       A callback for when the window size changes.
       @note WIP this might need to get fed back into the host somehow.
     */
-    virtual void sizeChanged(uint width, uint height)
+    virtual void sizeChanged(uint /* width */, uint /* height */)
     {
         // unused, meant for custom implementations
-        return; (void)width; (void)height;
     }
 
    /**
       A callback for when the window title changes.
       @note WIP this might need to get fed back into the host somehow.
     */
-    virtual void titleChanged(const char* title)
+    virtual void titleChanged(const char* /* title */)
     {
         // unused, meant for custom implementations
-        return; (void)title;
     }
 
    /**
       A callback for when the window visibility changes.
       @note WIP this might need to get fed back into the host somehow.
     */
-    virtual void visibilityChanged(bool visible)
+    virtual void visibilityChanged(bool /* visible */)
     {
         // unused, meant for custom implementations
-        return; (void)visible;
     }
 
    /**
       A callback for when the transient parent window changes.
     */
-    virtual void transientParentWindowChanged(uintptr_t winId)
+    virtual void transientParentWindowChanged(uintptr_t /* winId */)
     {
         // unused, meant for custom implementations
-        return; (void)winId;
     }
 
 private:
@@ -533,6 +546,9 @@ private:
         uint height;
         double scaleFactor;
         String title;
+        uint minWidth;
+        uint minHeight;
+        bool keepAspectRatio;
         bool isQuitting;
         bool isStandalone;
         bool visible;
@@ -544,6 +560,9 @@ private:
               height(1),
               scaleFactor(1.0),
               title(),
+              minWidth(0),
+              minHeight(0),
+              keepAspectRatio(false),
               isQuitting(false),
               isStandalone(false),
               visible(false) {}
diff --git a/distrho/src/DistrhoUIInternal.hpp b/distrho/src/DistrhoUIInternal.hpp
index e22a5787..af2764e8 100644
--- a/distrho/src/DistrhoUIInternal.hpp
+++ b/distrho/src/DistrhoUIInternal.hpp
@@ -132,9 +132,16 @@ public:
         return uiData->window->getScaleFactor();
     }
 
-    Size<uint> getMinimumSizeConstraint(bool& keepAspectRatio)
+    bool getGeometryConstraints(uint& minimumWidth, uint& minimumHeight, bool& keepAspectRatio) const noexcept
     {
-        return uiData->window->getMinimumSizeConstraint(keepAspectRatio);
+#if DISTRHO_PLUGIN_HAS_EXTERNAL_UI
+        uiData->window->getGeometryConstraints(minimumWidth, minimumHeight, keepAspectRatio);
+#else
+        const Size<uint> size(uiData->window->getGeometryConstraints(keepAspectRatio));
+        minimumWidth = size.getWidth();
+        minimumHeight = size.getHeight();
+#endif
+        return true;
     }
 
     bool isResizable() const noexcept
@@ -272,8 +279,10 @@ public:
     void setWindowSizeForVST3(const uint width, const uint height)
     {
         ui->setSize(width, height);
+#if !DISTRHO_PLUGIN_HAS_EXTERNAL_UI
         uiData->window->setSize(width, height);
         // uiData->app.idle();
+#endif
     }
 
     void setWindowTitle(const char* const uiTitle)
diff --git a/distrho/src/DistrhoUIPrivateData.hpp b/distrho/src/DistrhoUIPrivateData.hpp
index 1b63a33e..1371b9d2 100644
--- a/distrho/src/DistrhoUIPrivateData.hpp
+++ b/distrho/src/DistrhoUIPrivateData.hpp
@@ -152,6 +152,12 @@ public:
     void setTitle(const char* const title) { ui->setTitle(title); }
     void setVisible(const bool visible) { ui->setVisible(visible); }
     uintptr_t getNativeWindowHandle() const noexcept { return ui->getNativeWindowHandle(); }
+    void getGeometryConstraints(uint& minimumWidth, uint& minimumHeight, bool& keepAspectRatio) const noexcept
+    {
+        minimumWidth = ui->pData.minWidth;
+        minimumHeight = ui->pData.minHeight;
+        keepAspectRatio = ui->pData.keepAspectRatio;
+    }
 
     DISTRHO_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(PluginWindow)
 };
diff --git a/distrho/src/DistrhoUIVST3.cpp b/distrho/src/DistrhoUIVST3.cpp
index b156616e..81c1e868 100644
--- a/distrho/src/DistrhoUIVST3.cpp
+++ b/distrho/src/DistrhoUIVST3.cpp
@@ -75,10 +75,11 @@ struct ScopedUTF16String {
 
 // --------------------------------------------------------------------------------------------------------------------
 
-static bool checkSizeConstraint(const Size<uint>& size, const bool keepAspectRatio, v3_view_rect* const rect)
+static bool checkSizeConstraint(const uint minimumWidth, const uint minimumHeight, const bool keepAspectRatio,
+                                v3_view_rect* const rect)
 {
-    const int32_t minWidth = static_cast<int32_t>(size.getWidth());
-    const int32_t minHeight = static_cast<int32_t>(size.getHeight());
+    const int32_t minWidth = static_cast<int32_t>(minimumWidth);
+    const int32_t minHeight = static_cast<int32_t>(minimumHeight);
     bool changed = false;
 
     if (keepAspectRatio)
@@ -92,10 +93,10 @@ static bool checkSizeConstraint(const Size<uint>& size, const bool keepAspectRat
 
             // fix width
             if (reqRatio > ratio)
-                rect->right = static_cast<uint>(rect->bottom * ratio + 0.5);
+                rect->right = static_cast<int32_t>(rect->bottom * ratio + 0.5);
             // fix height
             else
-                rect->bottom = static_cast<uint>(static_cast<double>(rect->right) / ratio + 0.5);
+                rect->bottom = static_cast<int32_t>(static_cast<double>(rect->right) / ratio + 0.5);
         }
     }
 
@@ -255,9 +256,10 @@ public:
 
     v3_result checkSizeConstraint(v3_view_rect* const rect)
     {
+        uint minimumWidth, minimumHeight;
         bool keepAspectRatio;
-        const Size<uint> size(fUI.getMinimumSizeConstraint(keepAspectRatio));
-        return ::checkSizeConstraint(size, keepAspectRatio, rect) ? V3_FALSE : V3_TRUE;
+        fUI.getGeometryConstraints(minimumWidth, minimumHeight, keepAspectRatio);
+        return ::checkSizeConstraint(minimumWidth, minimumHeight, keepAspectRatio, rect) ? V3_FALSE : V3_TRUE;
     }
 
     // ----------------------------------------------------------------------------------------------------------------
@@ -1261,9 +1263,10 @@ struct dpf_plugin_view : v3_plugin_view_cpp {
         UIExporter tmpUI(nullptr, 0, view->sampleRate,
                          nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                          view->instancePointer, scaleFactor);
+        uint minimumWidth, minimumHeight;
         bool keepAspectRatio;
-        const Size<uint> size(tmpUI.getMinimumSizeConstraint(keepAspectRatio));
-        return ::checkSizeConstraint(size, keepAspectRatio, rect) ? V3_FALSE : V3_TRUE;
+        tmpUI.getGeometryConstraints(minimumWidth, minimumHeight, keepAspectRatio);
+        return ::checkSizeConstraint(minimumWidth, minimumHeight, keepAspectRatio, rect) ? V3_FALSE : V3_TRUE;
     }
 };