modules/graphics/src/main/java/com/sun/glass/ui/Window.java

*** 1,7 ****
  /*
!  * Copyright (c) 2010, 2017, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
--- 1,7 ----
  /*
!  * Copyright (c) 2010, 2018, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
*** 293,302 ****
--- 293,305 ----
  
          this.ptr = _createChildWindow(parent);
          if (this.ptr == 0L) {
              throw new RuntimeException("could not create platform window");
          }
+         if (screen == null) {
+             screen = Screen.getMainScreen(); // start with a default
+         }
      }
  
      public boolean isClosed() {
          Application.checkEventThread();
          return this.ptr == 0L;