Delivery start date is set automatically based on the available clicks.
The slider to select the number of clicks now can select from the minimum to the maximum number of clicks the seller offers per one solo ad order. But now it also changes the delivery date.
If the delivery date is set manually, it will prevent changing the date when the slider is moved to the lower number of clicks.
However, if you select the higher number of clicks than it's available for the selected date, it will change the date. It will also make the date to change when a lower number of clicks selected.