diff --git a/src/wxxt/src/Windows/Canvas.cc b/src/wxxt/src/Windows/Canvas.cc
index 5d565c4d82..fa62b56563 100644
--- a/src/wxxt/src/Windows/Canvas.cc
+++ b/src/wxxt/src/Windows/Canvas.cc
@@ -362,7 +362,7 @@ void wxCanvas::SetScrollbars(int h_pixels, int v_pixels, int x_len, int y_len,
 	XtVaSetValues(X->scroll,
 		      XtNhScrollAmount, h_units,
 		      XtNvScrollAmount, v_units,
-		      0);
+		      NULL);
       }
     } else {
       Arg a[8];
diff --git a/src/wxxt/src/Windows/Frame.cc b/src/wxxt/src/Windows/Frame.cc
index 1fad991b89..0bff04c61e 100644
--- a/src/wxxt/src/Windows/Frame.cc
+++ b/src/wxxt/src/Windows/Frame.cc
@@ -642,7 +642,7 @@ void wxFrame::SetIcon(wxBitmap *icon, wxBitmap *mask, int kind)
       pm = mask ? GETPIXMAP(mask) : (Pixmap)NULL;
       XtVaSetValues(X->frame, XtNiconMask, pm, NULL);
       pm = GETPIXMAP(bm);
-      XtVaSetValues(X->frame, XtNiconPixmap, pm, (Pixmap)NULL);
+      XtVaSetValues(X->frame, XtNiconPixmap, pm, (Pixmap)NULL, NULL);
       
       frame_icon = bm;
       frame_mask = mask;