ON GIVING FLUID INTERFACES AN ANCHOR

Summary from the TLDR Design newsletter

Interfaces that continuously reshape themselves in response to context, AI, or user intent risk becoming difficult to understand because people lose the stable landmarks they use to build a mental model of a product. Keeping frequently used action buttons anchored while content expands gives users a predictable place to click or tap as the interface changes. Fluid interfaces therefore work best when adaptability is balanced with enough permanence for users to understand where they are, what changed, and how to get back.