Icons with .ico extension aren't displayed in the 'Applications' menu
Example: 'xonotic' project installs the icon /usr/local/share/pixmaps/xonotic.ico file:
$ file /usr/local/share/pixmaps/xonotic.ico
/usr/local/share/pixmaps/xonotic.ico: MS Windows icon resource - 9 icons, 64x64, 32 bits/pixel, 16x16, 32 bits/pixel
It is displayed in the menu with an unknown icon.
XFCE-4 is installed from ports.
FreeBSD 13.1 STABLE