6853146: Regression: on-the-spot input is broken in AWT Peered components

Reviewed-by: art, ant, naoto

src/windows/native/sun/windows/awt_TextComponent.cpp

@@ -191,8 +191,11 @@ void AwtTextComponent::SetCompositionWindow(RECT& rc)
 {
     HIMC hIMC = ImmGetContext();
     // rc is not used for text component.
-    COMPOSITIONFORM cf = { CFS_POINT, {0,0}, {0,0,0,0} };
+    COMPOSITIONFORM cf = { CFS_FORCE_POSITION, {0,0}, {0,0,0,0} };
     GetCaretPos(&(cf.ptCurrentPos));
+    // the proxy is the native focus owner and it contains the composition window
+    // let's convert the position to a coordinate space relative to proxy
+    ::MapWindowPoints(GetHWnd(), GetProxyFocusOwner(), (LPPOINT)&cf.ptCurrentPos, 1);
     ImmSetCompositionWindow(hIMC, &cf);
 
     LOGFONT lf;