How to make rows disappear from tableview

Hi
I am developing a splitview based app for Ipad.It creates a master view and a detail view.My master view is a tableview.Actually I want a certain number of rows in my tableview. When I select that by overriding the appropriate function in DataSource (which is derived from UITableViewSource) I do get those rows in my view.But what I find is that below those rows also there are some rows which are not clickable . The rows that I selected are clickable with currently selected row being shown blue.I dont want these rows that appear below my selected rows.
When I try to decrease the height of the tableview in Interface builder ,it doesnt reflect when I run the app,in other words the tabelview height remains the same. Same happens with width..

Any ideas how I could make those rows dissappear ??Many thanks in advance.. Thx Akaash