Focus mode is a crucial feature for understanding what you’re editing in the site editor and avoiding unintended changes to your block theme.
When editing templates, some blocks belong to that specific template while others (like header template parts) are shared across multiple templates. Focus mode kicks in when you edit shared elements to make it crystal clear you’re affecting your entire site.
Double-click or select and click “Edit” on a template part or synced pattern to enter focus mode. The interface changes to show you’re editing that specific element in isolation, preventing accidental changes to your broader block theme structure.
This visual distinction helps you understand scope – are you editing just this template, or something that will change everywhere? Focus mode ensures you always know the impact of your changes when building block themes.