KB203: Set Default page in Visual WebGui Project

1. Open web.config file and locate <Applications> Tag
2. Set the <Application Code="[Symbolic Name]" Type="[Namespace].[Form Name], [Namespace]"/>

   <sample code="goes here" />

   Where the [Symbolic Name] is an alias to the [Form Name] that represent the startup page, and the [Namespace] is the application namespace.  
3. Right click on the project node in the solution explorer
4. Click on the properties menu item
5. Click on the Web tab
6. Select the Specific page in the Start Action and set the text box value to [Symbolic Name].wgx.
7. Save all your changes
8. Rebuild youe solution.