What is this line on my UITableView?

I have a grouped table view. I've made tens of table views before, but I'm not sure what this line is:

Can anyone tell me what that is and how to remove it?

UPDATE:

I narrowed down the problem to the heightForRowAtIndexPath delegate method. Take a look at that below. Note that I need some of the rows to be taller:

-(CGFloat)tableView:(UITableView *)tableViewLocal heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    if(indexPath.section == 0 && (indexPath.row开发者_开发问答 == 3 || indexPath.row == 4 || indexPath.row == 5))  {
        return tableViewLocal.rowHeight * 1.3; //If I remove the multiplier, it doesn't produce the line.
    }
    else
        return tableViewLocal.rowHeight;
}

It looks like the background. Try setting your tableView in code to

self.tableView.backgroundColor = [UIColor clearColor];

Hope this helps.