gnome – IBus input methods can’t work only in system search

I can type Chinese characters with IBus everywhere (gedit, vs-code…), BUT can’t input in the system search (the search bar that appears after pressing the Left-Super key) only.

After switch to some Chinese IME, and typping, Chinese characters appears in candidate area, but can’t post into system search textbox.

os: ubuntu 20.04 (disable all gnome-extensions).

A mirro question here: IBus input methods work only in system search