Sets the row selection flags for a range of rows.
setSelectionRange( name STRING, start INTEGER, end INTEGER, value BOOLEAN )
ON ACTION select_all CALL DIALOG.setSelectionRange( "sr", 1, -1, TRUE)
The start and end index must be in the range of possible row indexes (from 1 to DIALOG.getArrayLength()).
If you specify an end index of -1, it will set the flags from start index to the end of the list.