You don’t need to set the RGB colors to 0, you must set the Alpha value to 0, this is why it’s called RGBA =).
I quote,
" Make a copy of the file called default-config.js, rename the now copied file to config.js, edit it in notepad/notepad++, and change the line that says
background: 'rgba(52, 73, 94, 0.7)',
tobackground: 'rgba(52, 73, 94, 0.0)',
"
Please use the search function next time, thanks.