Running from terminal:
Gtk-Message: 10:24:52.056: Failed to load module "appmenu-gtk-module"
(gimp:134091): Gtk-WARNING **: 10:24:52.059: Unable to locate theme engine in module_path: "adwaita",
New gegl requires that GIMP has graphviz installed now, rebuild gimp is up (with that new depend added).
You can fix it without this rebuild by:
sudo pacman -S graphviz
Thanks! It works!