Version 72.0.3591.0(Official build) unknown(32-bit)
Platform 11195.0.0（official build) dev-channel kevin test
Firmware Google_Kevin.8785.264.0
Google_Input_Tools_Version:72.0.20181029.219244077


REPRO STEPS:
1.Switch to Pinyin keyboard.
2.Touch the top-left Arrow button to hide buttons (e.g. HW, Settings) on the first line.
3.Type something.
4.Submit any candidates or press Backspace to remove suggestion.

Actual result: 
The hide buttons (e.g. HW, Settings) show automatically.

Expected:
It should only show/hide buttons(e.g. HW, Settings) on the first line.