The code you posted works but propably not as you expect.
- You are adding the new Tab in TabHost1_Click event, it's not the best place.
- You are loading the same layout in the new tab ?
- You don't need a Panel in the tab layouts.
In the attached modifyed version the new tab is added with the Add button.
Be aware that once you have added a Tab you can't remove it.
Best regards.