If parentid is not specified, or contains a numeric 0, the value of row is multiplied by two. This code is believed to be a holdover from the days when the first 24 line terminals appeared, replacing the 12 line models. (This parameter was previously called "v," apparently a reference to the original VT-xxx terminals that made the transition from 12 to 24 lines.) Note that despite the "parent" in the parameter name, it is also possible to use it to name the current control, but that "parent" was chosen because in the vast majority of cases, that will be the main significance of the parameter.
(GUI) If parentid is numeric and greater than 1, it is interpreted as referencing the parent control whose ID is parentid-1. The current field is treated as a child of that control, which among other things means that its coordinates are taken as relative to the parent, allowing them to be relocated simply by relocated the parent, e.g. dialog, groupbox, tab control, etc.
(GUI) If parentid is a string, it can identify the name of the parent control rather than its ID number. It can also assign a name to the current control by preceding it with the character ">". If specifying both, start with the parent control name, then the ">", then the current (edit) control name. For example:
MAP1 PARENTID,S,50
parentid = "dlgCustomer"
parentid = "dlgCustomer>editName"
parentid = ">editfName"
Note that if parentid contains the name to be assigned to the current INFLD control, it must be preceded by a ">", and it must follow the parent control name, if present (as in the examples above). The maximum length of a control name is 24 characters. See Control names for more details on the concept of identifying controls with names.
