In which view can you NOT apply changes to the app interface to affect the user experience?

The test view is specifically designed for testing the functionality of the application rather than modifying its appearance or user interface. While in this view, you can run the app and interact with it as an end user would, you do not have the capability to make any changes to the app's interface elements.

In contrast, the layout view, design view, and configuration view are all areas where you can manipulate various aspects of the application's interface. The layout view allows for adjustments in the positioning and appearance of interface elements to enhance visual appeal or functionality. The design view is where a significant portion of the app’s foundational setup happens, including configuring tools and settings that define the app’s behavior, while the configuration view specifically lets you customize input and output settings along with other parameters. Therefore, the correct choice highlights the restriction of the test view in terms of making interface adjustments.