Get the index of the currently selected string, if any, in a list box. The index is stored in an environment variable called LBGET.
LBGET dlg_id id
dlg_id Specifies the identifier of the dialog box that contains the list box. id Specifies the identifier of the list box.
The index returned is zero based, that is, the first string in the list box is at index 0, the second string is at index 1 and so on.
When the list box does not contain a currently selected string then a value of -1 is returned.