Icon of the 'fltk' project isn't displayed in the 'Applications' menu and also in the whiskers menu
fltk-1.3.5 installs /usr/local/share/applications/fluid.desktop:
[Desktop Entry]
Name=FLUID
Comment=FLTK GUI Designer
TryExec=fluid
Exec=fluid %F
Icon=fluid
Terminal=false
Type=Application
MimeType=application/x-fluid;
Categories=Development;GUIDesigner;
and these icons:
/usr/local/share/icons/hicolor/128x128/apps/fluid.png
/usr/local/share/icons/hicolor/32x32/apps/fluid.png
/usr/local/share/icons/hicolor/48x48/apps/fluid.png
/usr/local/share/icons/hicolor/64x64/apps/fluid.png
"Fluid" item appears in the menu but without the proper icon.
xfce4-desktop-4.16.0 FreeBSD 12.2