Theme Options Hex codes

Hi,
I can’t see the custom color HEX input in my Theme Options. I’ve already edit the file

\includes\ext\option-tree\assets\css\ot-admin.css

with

/*
.hide-color-picker {
display: none;
}
*/

but it doesn’t work. Is this the right code? Is there a specific position where I have to put it in the file?

Thanks