(a)
In your InputScript, add an "Enter" for the current screen and a "Screen"
command. After the "Screen" command "&F[Order type]" will have the new value.
(b)
Define the drop down list differently so that the value is put into your own
variable, and then use an InputScript to put the selected value into F[Order
type]:
DropDownList (12,59) "Order type" refer="V[myOrderType]"
width=25 process="SetOrderType.txt"
InputScript "SetOrderType.txt"
Set F[Order type] "&V[myOrderType]"
Return