I think it is the problem of SynEdit, it does not accept Chinese input method, the other controls are accepted Chinese input method.
我感觉是 SynEdit 的问题,它不接受中文输入法,其它控件都接受中文输入法。
I underestimated this issue, SynEdit can not call IME (input method) under Linux, this is a long history, a serious bug.
These days, I set up two Linux distributions and installed Lazaurs, confirming what you said about SynEdit's inability to type Chinese. The environment is: ubuntu desktop 16.04.3, Dellpin Linux 15.5, both environments will fail to call the Fctix IME or ibus IME in the Lazaru Code Editor.
Since Lazarus uses SynEdit, his bug is Lazarus's bug, and the history of SynEdit can be found on the FPC official wiki.
http://wiki.freepascal.org/SynEdit (我低估了这个问题,SynEdit在Linux下不能调用输入法,这是一个历史悠久的、严重bug。哥们别灰心,咱们再努力)