Expression in time (perspective)

Hi everybody)
I have an issue with creating the period. Basically problem is Custom Period: when I want to set up the date and time in popup-calendar it changing automatically in a second to “Custom”, dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd HH:mm:ss”)

this is my code for start date :
CAse ({…/Period.props.value},
“Past 30 Min”,dateFormat(dateArithmetic(now(),-30, “Minute”), “yyyy-MM-dd HH:mm:ss”),
“Past Hour”, dateFormat(dateArithmetic(now(),-1, “Hour”), “yyyy-MM-dd HH:mm:ss”),
“Past 2 Hour”, dateFormat(dateArithmetic(now(),-2, “Hour”), “yyyy-MM-dd HH:mm:ss”),
“Past 4 Hour”, dateFormat(dateArithmetic(now(),-4, “Hour”), “yyyy-MM-dd HH:mm:ss”),
“Past 8 Hour”, dateFormat(dateArithmetic(now(),-8, “Hour”), “yyyy-MM-dd HH:mm:ss”),
“Current Day”, dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd 00:00:00”),

“Morning”, (if (dateFormat(dateArithmetic(now(),0, “Day”), “HH:mm:ss”)<“2:30:00”,
dateFormat(dateArithmetic(now(0),-1, “Day”), “yyyy-MM-dd 2:30:00”),dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd 2:30:00”))),

“Daylight”, (if (dateFormat(dateArithmetic(now(),0, “Day”), “HH:mm:ss”)<“7:30:00”,
dateFormat(dateArithmetic(now(0),-1, “Day”), “yyyy-MM-dd 7:30:00”),dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd 7:30:00”))),

“Twilight”, (if (dateFormat(dateArithmetic(now(),0, “Hours”), “HH:mm:ss”)<“13:00:00”,
dateFormat(dateArithmetic(now(0),-1, “Day”), “yyyy-MM-dd 13:00:00”),dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd 13:00:00”))),

“Night”, (if (dateFormat(dateArithmetic(now(),0, “Day”), “HH:mm:ss”)<“18:30:00”,
dateFormat(dateArithmetic(now(0),-1, “Day”), “yyyy-MM-dd 18:30:00”),dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd 18:30:00”))),

“Wrap Down”, (if (dateFormat(dateArithmetic(now(),0, “Day”), “HH:mm:ss”)<“23:30:00”,
dateFormat(dateArithmetic(now(0),-1, “Day”), “yyyy-MM-dd 23:30:00”),dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd 23:30:00”))),

“Current Sort”,
if (dateFormat(dateArithmetic(now(),0, “Day”), “HH:mm:ss”)<“7:30:00”, dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd 2:30:00”),
if (dateFormat(dateArithmetic(now(),0, “Day”), “HH:mm:ss”)<“13:00:00”, dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd 7:30:00”),
if (dateFormat(dateArithmetic(now(),0, “Day”), “HH:mm:ss”)<“18:30:00”, dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd 13:00:00”),
if (dateFormat(dateArithmetic(now(),0, “Day”), “HH:mm:ss”)<“23:30:00”, dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd 18:30:00”),
if (dateFormat(dateArithmetic(now(),0, “Day”), “HH:mm:ss”)<“2:30:00”, dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd 23:30:00”),
dateFormat(dateArithmetic(now(),0, “Day”), “yyyy-MM-dd HH:mm:ss”)))))),

“Custom”, dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd HH:mm:ss”),
dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd HH:mm:ss”))

Next Code from end date(only custom period):
“Custom”,if (dateIsBetween(dateFormat(dateArithmetic(now(0),0, “Day”), “yyyy-MM-dd HH:mm:ss”), toDate({…/StartTime.props.value}), toDate(dateFormat(dateArithmetic({…/StartTime.props.value}, 7, “day”), “yyyy-MM-dd HH:00:00”))),
todate(dateFormat(dateArithmetic(now(0), 0, “Day”), “yyyy-MM-dd HH:00:00”)),toDate(dateFormat(dateArithmetic({…/StartTime.props.value}, 7, “day”), “yyyy-MM-dd HH:00:00”))),