The Fixed Background Setting Doesn’t Work on Mobile

Stackable disables the Fixed Background setting on mobile since it tends to work inconsistently in most mobile devices. 

IMPORTANT: Please note that background-attachment: fixed CSS fix is not widely supported in mobile browsers. Please check this resource for more information: https://caniuse.com/background-attachment

To force the background image to be fixed , you can try to add this Custom CSS to your block: 

@media screen and (max-width: 768px) {
    > .stk-container {
        background-attachment: fixed;
    }
}

Or

@media screen and (max-width: 768px) {
    .stk-block {
        background-attachment: fixed;
    }
}