Selects the previous row containing a match.
@private
function() {
        var me = this,
            idx;
            
        if ((idx = Ext.Array.indexOf(me.indexes, me.currentIndex)) !== -1) {
            me.currentIndex = me.indexes[idx - 1] || me.indexes[me.indexes.length - 1];
            me.getSelectionModel().select(me.currentIndex);
         }
    }