ListGrid tied to ds making save call on edited record even autoSaveEdits:false

We have an editable ListGrid tied to datasource and one of the column type is comboBox, which on changing and tabbing out of the column makes a server SAVE action even when the ListGrid properties set to autoSaveEdits: false, editOnFocus: true,canEdit: true,alwaysShowEditors: true,confirmDiscardEdits: false

Note: This happens only to the last row change and tabbing out of the editable column.

SmartClient Version: isc_version=v9.1p_2015-06-04.js

Browser: All browsers, Windows 7 & 8.

isomorphic/IDACall?isc_rpc=1&isc_v=v9.1p_2015-06-04&isc_xhr=1 HTTP/1.1

Appreciate if you can let us know what is triggering this and how to prevent, as we want all the save to happen on clicking the button and calling ListGrid's saveAllEdits();