Having the same issue in Ubuntu Karmic. I hope, that will be fixed with upgrade. The way to reproduce: enter network manager editor, select wired connection, select 'Manual' in ipv4 tab, set your params, click 'Ok' and see, that nothing changed. After re-opening of nm-connection-editor there's still DHCP there. (Ubuntu Karmic beta).
Having the same issue in Ubuntu Karmic. I hope, that will be fixed with upgrade. The way to reproduce: enter network manager editor, select wired connection, select 'Manual' in ipv4 tab, set your params, click 'Ok' and see, that nothing changed. After re-opening of nm-connection- editor there's still DHCP there. (Ubuntu Karmic beta).