Up to the questions:
- The highlighted option in the Properties pane (see the attached screenshot) controls whether the corresponding assembly will be included in the XAP file, or not. However, when loading the additional XAP files, you should take care of loading the assemblies (or use Prism or other framework that will take care of them for you). For example, our online demos' initial XAP file contains only the Controls, Input and Navigation assemblies, plus the empty demo application. When you click on GridView, for example, we load an additional XAP file, that contains the GridView assembly and the GridView examples.
- Yes, you need to do a full rebuild.
the Telerik team