This addon adds a small window with a button in it which can be clicked and moved around. When clicking on it, it will switch hold to cast on or off.
The window can be shown by using the command /fhtc which is an abbreviation of "Fast "Hold" "To" "Cast".There's no option to hide the window yet and it will always spawn at the top left after reload ui or when logging in.
Might come in future versions depending on the interest of people.