diff --git a/src/display/plane.cpp b/src/display/plane.cpp
index 5b834cdc..27e64c22 100644
--- a/src/display/plane.cpp
+++ b/src/display/plane.cpp
@@ -161,8 +161,13 @@ struct PlanePrivate
 	}
 };
 
+static void disposePtr(void *ptr)
+{
+	((Plane *)ptr)->dispose();
+}
+
 Plane::Plane(Viewport *viewport)
-    : ViewportElement(viewport)
+    : ViewportElement(disposePtr, viewport)
 {
 	p = new PlanePrivate();
 
diff --git a/src/display/sprite.cpp b/src/display/sprite.cpp
index 81de31fe..af3578f6 100644
--- a/src/display/sprite.cpp
+++ b/src/display/sprite.cpp
@@ -342,8 +342,13 @@ struct SpritePrivate
     }
 };
 
+static void disposePtr(void *ptr)
+{
+    ((Sprite *)ptr)->dispose();
+}
+
 Sprite::Sprite(Viewport *viewport)
-: ViewportElement(viewport)
+: ViewportElement(disposePtr, viewport)
 {
     p = new SpritePrivate;
     onGeometryChange(scene->getGeometry());
diff --git a/src/display/tilemap.cpp b/src/display/tilemap.cpp
index 83e6c0b4..dacfa976 100644
--- a/src/display/tilemap.cpp
+++ b/src/display/tilemap.cpp
@@ -1076,7 +1076,7 @@ struct TilemapPrivate
 };
 
 GroundLayer::GroundLayer(TilemapPrivate *p, Viewport *viewport)
-    : ViewportElement(viewport, 0),
+    : ViewportElement(nullptr, viewport, 0),
       vboCount(0),
       p(p)
 {
@@ -1126,7 +1126,7 @@ void GroundLayer::onGeometryChange(const Scene::Geometry &geo)
 }
 
 ZLayer::ZLayer(TilemapPrivate *p, Viewport *viewport)
-    : ViewportElement(viewport, 0),
+    : ViewportElement(nullptr, viewport, 0),
       index(0),
       vboOffset(0),
       vboCount(0),
diff --git a/src/display/tilemapvx.cpp b/src/display/tilemapvx.cpp
index b4260a50..c1144dd5 100644
--- a/src/display/tilemapvx.cpp
+++ b/src/display/tilemapvx.cpp
@@ -103,7 +103,7 @@ struct TilemapVXPrivate : public ViewportElement, TileAtlasVX::Reader
 		TilemapVXPrivate *p;
 
 		AboveLayer(TilemapVXPrivate *p, Viewport *viewport)
-		    : ViewportElement(viewport, 200),
+		    : ViewportElement(nullptr, viewport, 200),
 		      p(p)
 		{}
 
@@ -119,7 +119,7 @@ struct TilemapVXPrivate : public ViewportElement, TileAtlasVX::Reader
 	AboveLayer above;
 
 	TilemapVXPrivate(Viewport *viewport)
-	    : ViewportElement(viewport),
+	    : ViewportElement(nullptr, viewport),
 	      mapData(0),
 	      flags(0),
 	      allocQuads(0),
diff --git a/src/display/viewport.cpp b/src/display/viewport.cpp
index d8bd75f9..b822e5f4 100644
--- a/src/display/viewport.cpp
+++ b/src/display/viewport.cpp
@@ -223,9 +223,9 @@ void Viewport::releaseResources()
 }
 
 
-ViewportElement::ViewportElement(Viewport *viewport, int z, int spriteY)
+ViewportElement::ViewportElement(void (*dispose)(void *), Viewport *viewport, int z, int spriteY)
     : SceneElement(viewport ? *viewport : *shState->screen(), z, spriteY),
-      m_viewport(viewport)
+      m_dispose(dispose), m_viewport(viewport)
 {
 	if (rgssVer == 1 && viewport)
 		viewportDispCon = viewport->wasDisposed.connect(&ViewportElement::viewportElementDisposal, this);
@@ -252,9 +252,8 @@ void ViewportElement::setViewport(Viewport *viewport)
 void ViewportElement::viewportElementDisposal()
 {
 	viewportDispCon.disconnect();
-	Disposable *self = dynamic_cast<Disposable*>(this);
-	if(self != nullptr)
-		self->dispose();
+	if(m_dispose != nullptr)
+		m_dispose(this);
 }
 
 ViewportElement::~ViewportElement()
diff --git a/src/display/viewport.h b/src/display/viewport.h
index 20fdddd7..761eaadc 100644
--- a/src/display/viewport.h
+++ b/src/display/viewport.h
@@ -70,7 +70,7 @@ private:
 class ViewportElement : public SceneElement
 {
 public:
-	ViewportElement(Viewport *viewport = 0, int z = 0, int spriteY = 0);
+	ViewportElement(void (*dispose)(void *), Viewport *viewport = 0, int z = 0, int spriteY = 0);
 	~ViewportElement();
 
 	DECL_ATTR( Viewport,  Viewport* )
@@ -79,6 +79,7 @@ protected:
 	virtual void onViewportChange() {}
 
 private:
+	void (*m_dispose)(void *);
 	Viewport *m_viewport;
 	sigslot::connection viewportDispCon;
 	sigslot::connection viewportElementDispCon;
diff --git a/src/display/window.cpp b/src/display/window.cpp
index 8d35670e..79f93997 100644
--- a/src/display/window.cpp
+++ b/src/display/window.cpp
@@ -212,7 +212,7 @@ struct WindowPrivate
 
 		WindowControls(WindowPrivate *p,
 		               Viewport *viewport = 0)
-		    : ViewportElement(viewport),
+		    : ViewportElement(nullptr, viewport),
 		      p(p)
 		{
 			setZ(2);
@@ -695,8 +695,13 @@ struct WindowPrivate
 	}
 };
 
+static void disposePtr(void *ptr)
+{
+	((Window *)ptr)->dispose();
+}
+
 Window::Window(Viewport *viewport)
-	: ViewportElement(viewport)
+	: ViewportElement(disposePtr, viewport)
 {
 	p = new WindowPrivate(viewport);
 	onGeometryChange(scene->getGeometry());
diff --git a/src/display/windowvx.cpp b/src/display/windowvx.cpp
index dc98da1e..d23e3fd6 100644
--- a/src/display/windowvx.cpp
+++ b/src/display/windowvx.cpp
@@ -832,15 +832,20 @@ struct WindowVXPrivate
 	}
 };
 
+static void disposePtr(void *ptr)
+{
+	((WindowVX *)ptr)->dispose();
+}
+
 WindowVX::WindowVX(Viewport *viewport)
-    : ViewportElement(viewport, DEF_Z, DEF_SPRITE_Y)
+    : ViewportElement(disposePtr, viewport, DEF_Z, DEF_SPRITE_Y)
 {
 	p = new WindowVXPrivate(0, 0, 0, 0);
 	onGeometryChange(scene->getGeometry());
 }
 
 WindowVX::WindowVX(int x, int y, int width, int height)
-    : ViewportElement(0, DEF_Z, DEF_SPRITE_Y)
+    : ViewportElement(disposePtr, 0, DEF_Z, DEF_SPRITE_Y)
 {
 	p = new WindowVXPrivate(x, y, width, height);
 	onGeometryChange(scene->getGeometry());