Clicking the bundle app button allows you to add the previously activated application to the actually modified application. In this way the designer can create the powerful applications without the need to copy the common theme apps that can be reused.
To start bonding the applications, expand the menu of the application management (1), click the button (2) and select the application you want to link (3). Then accept the change (4) to see the effects.
The associated application will be visible in the designer as the additional tab: