Hi Indrajit,
How come you have 2 data sources? In order for the cascading filter to work, both the REGION and AREA dimensions should be in the same HANA View. So you only need one data source, DS_1. Both drop downs should specify DS_1 as the data source and there is no need to specify a Target Data Source unless you explicitly need to filter a second data source as well.
Regards,
Mustafa.