No Chinese character candidates poping up whne inputting Chinese using Pingyin

[XiaoGuo, Liu]

On Ubuntu touch Nexus 4 phone, I have switched to Chinese keyboard layout, and Pingyin input method is selected.

1) Open "note" application
2) type "b", there are no Chinese candidates
3) type "a", then it starts to appear some Chinese candiates, and "ba"' become purple color.

4) sometimes, when I input "b" only, it becomes purple. It is not consistent

In normal use case, whenever an end user types something, it should show some of the candidates starting with the letter (pingyin). For example, in the above example, when an end user inputs "b", it should start to show all of the candidates starting with "b" (pingyin). Otherwise, an end user may thing something may be wrong.