@Pjama, this is my Nickel Menu file; it works flawlessly on my Clara HD, although you have to do a shutdown (hold power button until the screen goes dark) and power up to have the toggling of Invert Mode take effect:
Code:
# Sunday, August 22, 2021, at 3:32 p.m.
# -------------------------------------------------------------------------
menu_item :main :Dark Mode :nickel_setting :toggle :dark_mode
menu_item :main :Invert Screen :nickel_setting :toggle: invert
menu_item :main :Portrait :nickel_orientation :portrait
menu_item :main :Landscape Right :nickel_orientation :landscape
menu_item :main :Landscape Left :nickel_orientation :inverted_landscape
menu_item :main :My Articles :nickel_open: library: pocket
menu_item :main :Screenshots :nickel_setting :toggle :screenshots
# -------------------------------------------------------------------------
menu_item :reader :Dark Mode :nickel_setting :toggle :dark_mode
menu_item :reader :Invert Screen :nickel_setting :toggle: invert
menu_item :reader :Portrait :nickel_orientation :portrait
menu_item :reader :Landscape Right :nickel_orientation :landscape
menu_item :reader :Landscape Left :nickel_orientation :inverted_landscape
menu_item :reader :My Articles :nickel_open: library: pocket
# -------------------------------------------------------------------------
menu_item :library :Dark Mode :nickel_setting :toggle :dark_mode
menu_item :library :Invert Screen :nickel_setting :toggle: invert
menu_item :library :Portrait :nickel_orientation :portrait
menu_item :library :Landscape Right :nickel_orientation :landscape
menu_item :library :Landscape Left :nickel_orientation :inverted_landscape
menu_item :library :My Articles :nickel_open: library: pocket
# ----------------------------------------------------------------------------