The parentid parameter determines the scope of the controls to which the focus can be moved using the Tab and Arrow keys, while waiting for an event. Note that unless the flags EVW_DESCEND and/or EVW_SIBLINGS are set, the focus will be limited to direct children of the specified group or dialog. To clarify this, consider the dialog below:
This dialog is made up of at least 3 groups. (The two buttons at the bottom may be direct children of the dialog, or they may be in their own invisible group, which is common but hard to detect visually.) If we set the parentid to the ID of the dialog, and do not set the EVW_DESCEND flag, then the user would not be able to move the focus to the radio buttons and edit boxes within the groups, because those are all grandchildren (rather than direct children) of the dialog. If the two icon buttons at the bottom were direct children of the dialog (not part of their own invisible group) then the focus would be limited to those two buttons. (That is, the Tab and Arrow keys would not permit the focus to be moved into any of the groupboxes.) The user, could, however, use the mouse to click on anything that generates an exitcode.
Similarly, if the parentid was set to the ID of the group "Destinos", then, the user could Arrow or Tab around within that groupbox but not go directly to another groupbox without first existing from the event wait operation (unless the EVW_SIBLINGS flag was set.).
History
2011 February, A-Shell 5.1.1205: You can now pass alphanumeric IDs for the parentid and ctlid parameters. This eliminates one of the most common excuses for needing a numeric control ID. Note, however, that the updated ctlid parameter will be returned as a number (although formatted as a string if you pass a string parameter). This shouldn't make any difference to your application as a string-formatted numeric control ID may be used anywhere an alphanumeric control ID may be used.
