I have recently updated one of the articles on the subject in our support knowledge base and wanted to test-drive this content with you: https://www.devexpress.com/kb=T271022
Since the Application Model basically represents a skeleton of the application UI, based on which visual controls for supported platforms are created at runtime, updates to various options in the source UI metadata (both at design time and runtime) can be a good and often platform-agnostic alternative to customizing underlying controls directly in Controllers or other UI entities (examples: one, two, three). The most difficult thing is to perform this update at the right moment or using the right event in the View life cycle!
Even though this may sound like a quite an advanced topic, this is one of the core concepts for our framework, which I recommend you get familiar with.
Your feedback is welcome, as always!
We also hope to use this KB as a base for future updates of the online documentation at Concepts > Application Model for easier discoverability, so your early feedback on the main methods I described is welcome. In particular, I would greatly appreciate your comments on whether you experienced the scenarios needed runtime Application Model updates and exactly which techniques you used (e.g., #2.1, 2.2 or all ).