1) without this fix: nothing even fcitx indicator doesn't show inside vncserver;
2) with this fix: only fcitx indicator shows inside vncserver, but I still cannot switch out charactor input panel to input any chinese charactors;
3) ignore BadValue exception: this fix works well, everything (both indicator and panel) came back to normal.
To be clear,
1) without this fix: nothing even fcitx indicator doesn't show inside vncserver;
2) with this fix: only fcitx indicator shows inside vncserver, but I still cannot switch out charactor input panel to input any chinese charactors;
3) ignore BadValue exception: this fix works well, everything (both indicator and panel) came back to normal.