Button long pressed with qt5 when click

[Doerthous]

Hello, I'm a newbie with ts and touchscreen app. I encountered some problems.

Problem

I'm working on an arm board with qt5 and tslib. I run the following command to start my app.
export QT_QPA_GENERIC_PLUGINS=tslib:/dev/input/event0 && ./main
When I click a button, the button keep pressed state until I click another button.

PLATFROM

• Qt 5.12
• tslib 0.9

Wish somebody can help me out. Thanks