diff --git a/scene_opengl.cpp b/scene_opengl.cpp
index 7cf0b186e4..5d9137a242 100644
--- a/scene_opengl.cpp
+++ b/scene_opengl.cpp
@@ -610,6 +610,7 @@ void SceneOpenGL::windowGeometryShapeChanged( Toplevel* c )
     Window& w = windows[ c ];
     w.discardShape();
     w.discardTexture();
+    w.discardVertices();
     }
 
 void SceneOpenGL::windowOpacityChanged( Toplevel* )
@@ -645,6 +646,7 @@ SceneOpenGL::Window::Window( Toplevel* c )
 void SceneOpenGL::Window::free()
     {
     discardTexture();
+    discardVertices();
     }
 
 void SceneOpenGL::Window::requestVertexGrid(int maxquadsize)
@@ -985,6 +987,13 @@ void SceneOpenGL::Window::discardTexture()
     texture = 0;
     }
 
+void SceneOpenGL::Window::discardVertices()
+{
+    // Causes list of vertices to be recreated before next rendering pass
+    currentXResolution = -1;
+    currentYResolution = -1;
+}
+
 // paint the window
 void SceneOpenGL::Window::performPaint( int mask, QRegion region, WindowPaintData data )
     {
diff --git a/scene_opengl.h b/scene_opengl.h
index 8fa73106c2..63a0757079 100644
--- a/scene_opengl.h
+++ b/scene_opengl.h
@@ -81,6 +81,7 @@ class SceneOpenGL::Window
         void enableTexture();
         void disableTexture();
         void discardTexture();
+        void discardVertices();
         Window() {} // QMap sucks even in Qt4
 
         /**