8189687: Swing: Invalid position of candidate pop-up of InputMethod in Hi-DPI on Windows

Reviewed-by: phh
Backport-of: 489e5ae3349370825b7faa1d7514796a2b1ac1c7

Author: Kazuhisa Takakuri

jdk/src/windows/native/sun/windows/awt_Component.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1996, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 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
@@ -3840,7 +3840,7 @@ void AwtComponent::OpenCandidateWindow(int x, int y)
 {
     UINT bits = 1;
     POINT p = {0, 0}; // upper left corner of the client area
-    HWND hWnd = GetHWnd();
+    HWND hWnd = ImmGetHWnd();
     if (!::IsWindowVisible(hWnd)) {
         return;
     }