Thank you Eric. Well,actually my Prolog is the latest version (9.0.4). Only Swi-Prolog Editor is 5.08. I could not really find the latest of this editor. If you know where it is could you please share with me? Also, yes I use Windows.
Looks like a SWI-Prolog Editor issue. SWI-Prolog itself can handle full Unicode (the Windows version added support for code points above 0xffff only recently, but that mostly affects emojis).
Raise it with the developers of SWI-Prolog Editor. The Windows editor project has nothing to do with SWI-Prolog. Sorry, we concentrate on portable tools.
A good alternative is to use plain SWI-Prolog that comes with its own tools or use GNU-Emacs with the “sweep” mode. See Sweep: SWI-Prolog Embedded in Emacs
There are also plugins for several other platforms such as Eclipse and VCS.