Cascaded filters in ssrs report

Hi,

i have 3 cascaded filters in ssrs report :

1. Region

2. Geomarket

3. Country

i have created 3 datasets for each of them in a cascaded fashion. everything works fine except the COUNTRY parameter which doesn't take the default values on its own like other parameters. I want the report to run automatically with default filters.

does any one know why this is happening.