Reproducible sample:

<window>
    <datebox />
</window>

Reproduce steps:
1. Open datebox popup in mobile device (test with android 4.2.1, Chrome 43.0.2357.92).
2. Scroll year to 2020, then click 'OK'.
3. Open datebox popup again.
4. Scroll year down to 202x, but it jump back to 198x.