The problem occurs in Linux Mint 17.2 Xfce 64-bit (linuxmint-17.2-xfce-64bit.iso) and earlier releases as well.
I noticed this problem after I installed the package "shimmer-themes" (version 1.7.3-0ubuntu1).
Several themes which cause desktop launchers to have a coloured label background are not displayed correctly. The font colour of the label also doesn't follow the specification from the theme.
I included a screenshot of the themes Adwaita and Albatross both in Linux Mint 17.2 Xfce RC (edit: it looks the same in the final release of 17.2 Xfce) and Xubuntu 15.04. The way the labels are displayed in Xubuntu is consistend with all others distros that I tested with Xfce4. Apparently all GTK themes are affected by this bug.
The always white label font color makes it hard to read the label in front of a bright wallpaper.
