--- a/gfx/thebes/src/gfxPlatformGtk.cpp
+++ b/gfx/thebes/src/gfxPlatformGtk.cpp
@@ -132,16 +132,19 @@ gfxPlatformGtk::CreateOffscreenSurface(c
         default:
             return nsnull;
     }
 
     // XXX we really need a different interface here, something that passes
     // in more context, including the display and/or target surface type that
     // we should try to match
     Display* display = GDK_DISPLAY();
+    if (!display)
+        return nsnull;
+
     if (!UseGlitz()) {
         GdkPixmap* pixmap = nsnull;
         XRenderPictFormat* xrenderFormat =
             XRenderFindStandardFormat(display, xrenderFormatID);
 
         if (!xrenderFormat) {
             // We don't have Render; see if we can just create a pixmap
             // of the requested depth.