IBus-sunpinyin/pinyin not working on ubuntu18.4

I have installed ibus-sunpinyin by following https://askubuntu.com/questions/59356/how-do-i-get-chinese-input-to-work/735139

I am using German keyboard and system language is English.

I could switch languages and see each icon of languages. But I can only input Chinese on desktop not on any apps.

Can somebody help? Thanks.

Our support channels, listed at https://community.ubuntu.com/t/finding-help/712, are full of skilled volunteers ready to offer a hand and good advice.

Since this is not a support channel, closing this thread. Sorry.