This is an annoyance, there are so many places to set the cursor:
cat .gtkrc-2.0
gtk-enable-animations=1
gtk-primary-button-warps-slider=0
# DO NOT EDIT! This file will be overwritten by LXAppearance.
# Any customization should be done in ~/.gtkrc-2.0.mine instead.
gtk-theme-name="Flat-Remix-GTK-Blue-Dark-Solid"
gtk-icon-theme-name="Hey-blue-dark"
gtk-font-name="Noto Sans, 13"
gtk-cursor-theme-name="Bibata-Modern-Amber"
gtk-cursor-theme-size=48
gtk-toolbar-style=3
gtk-toolbar-icon-size=GTK_ICON_SIZE_LARGE_TOOLBAR
gtk-button-images=1
gtk-menu-images=1
gtk-enable-event-sounds=1
gtk-enable-input-feedback-sounds=1
gtk-xft-antialias=1
gtk-xft-hinting=1
gtk-xft-hintstyle="hintfull"
gtk-xft-rgba="none"