Hi Visoth,
Try changing the Default Font in the Options pull down. Works in Windows, but having trouble in Linux.
Just as a side note to anyone interested: In the Options pull down menu click Fonts and then change the Default Font. For some reason the Chinese fonts would not work for me in Windows, but DejaVu did. In addition for Linux the Noto Sans CJK font works. If you can't get it to work, keep changing to a different font and be Patient