Ya as u say if we set the parameter to Boolean then we are able to set a default value.

But as we deploy the reports, and when we navigate from report1 ->report 2, the entire paramater tab is getting hidden automatically.

Every time I got click on the button show/hide parameters. In order to avoid this issue, I am trying to create a dummy param say iif 1=1,true/false... In such a case when I deploy, the parameter selection tab doesnt get hidden. I thot this would be a work around to display the parameter tab always..