diff --git a/video/out/vo_direct3d.c b/video/out/vo_direct3d.c
index 032454eb3f..34ddafdd1e 100644
--- a/video/out/vo_direct3d.c
+++ b/video/out/vo_direct3d.c
@@ -772,7 +772,8 @@ static bool resize_d3d(d3d_priv *priv)
 {
     D3DVIEWPORT9 vp = {0, 0, priv->vo->dwidth, priv->vo->dheight, 0, 1};
 
-    MP_VERBOSE(priv, "resize_d3d called.\n");
+    MP_VERBOSE(priv, "resize_d3d %dx%d called.\n",
+               priv->vo->dwidth, priv->vo->dheight);
 
     /* Make sure that backbuffer is large enough to accomodate the new
        viewport dimensions. Grow it if necessary. */
diff --git a/video/out/w32_common.c b/video/out/w32_common.c
index bc2a700975..f59c3cc259 100644
--- a/video/out/w32_common.c
+++ b/video/out/w32_common.c
@@ -515,6 +515,9 @@ static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
 {
     assert(w32_thread_context);
     struct vo_w32_state *w32 = w32_thread_context;
+    if (!w32->window)
+        w32->window = hWnd; // can happen during CreateWindow*!
+    assert(w32->window == hWnd);
     int mouse_button = 0;
 
     switch (message) {
@@ -522,7 +525,7 @@ static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
         // This message is used to wakeup the GUI thread, see wakeup_gui_thread.
         mp_dispatch_queue_process(w32->dispatch, 0);
         break;
-    case WM_ERASEBKGND: // no need to erase background seperately
+    case WM_ERASEBKGND: // no need to erase background separately
         return 1;
     case WM_PAINT:
         signal_events(w32, VO_EVENT_EXPOSE);