Your code is obsolete, which may be the reason it doesn't work as intended. The recommended way if you are using the latest version 0.9.7 is:
$('div#example1').handsontable(options);
//get the instance using jQuery wrapper
var ht = $('#example1').handsontable('getInstance');
//Return index of the currently selected cells as an array [startRow, startCol, endRow, endCol]
var sel = ht.getSelected();
//'alert' the index of the starting row of the selection
alert(sel[0]);
If you are using an older version I suggest downloading the latest version.
EDIT:
As suggested by @polras, you can also add:
outsideClickDeselects: false
to handsonetable options