[macOS] Korean Hangul-Hanja conversion does not work as expected

Platform: macOS High Sierra 10.13.6 Korean

Korean IME's Hangul-Hanja conversion does not work on AWT TextField/
TextArea and Swing components.

To see this issue, I use IMFDemo sample program [1]

Test instruction is as follows:
1. Compile IMFDemo and run it
2. Move input focus to "Lightweight component, active client"
3. Turn on Korean IME
4. Type "gks", then press Option+Return key to display candidate window
5. Press "1", then Hanja is commeted, but Hangul and Hanja characters are committed.
   (Candiate window is displayed, but it seems Hangul character is committed)
6. Move input focus to "Peer Component"
7. Type "gks", then press Option+Return key to display candidate window
8. Press "1", then Hanja is commeted, but Hangul and Hanja characters are committed.

I tried to follow same instruction on TextEditor App and Java AWT FileDialog component, it worked fine (Only Hanja character was committed)

Movie (korean-ime-macos.mov) was attached

[1] https://docs.oracle.com/javase/8/docs/technotes/guides/imf/api-tutorial.html#Sample__Code