XFCE notification - white underline displayed below the pop-up

[kepler2]

Hello!

First of all thanks for you work!

I've found an issue. In XFCE, there is a white underline beneath the actual notification pop-up.

Note that the theme does not have an "Amber" entry in Notification settings so it's set to default.

Screenshot(s)

Versions:
OS : Arch
DE : XFCE 4.14
Name : amber-theme-git
Version : r201.1439f2a-1

Regards.