After having loaded the project in the IDE:
- open the Designer
- you will see two windows, one for the Designer and one for the Abstract Designer.
- in the Abstract Designer you will see only a text 'This is the Abstract Designer Connected to...'
- to show a layout file you must in the Designer click on the menu File
- there you will see at the bottom of the menu the list of the projects layout files
- click on one of those to show it
- in the case of the UserInterfaceTabHost example you should see : Main, page1, page2 and page3 click on one of those to show that layout.
Best regards.