Focus mode for global regions

We'll need a UI component (or set of components) to display the name of the currently focused region in the top bar, and allow exiting from focus via clicking it. This will need to be coordinated with the work in #3489106.

Once 🐛 Empty global regions add unnecessary spacing to preview Active is fixed, this issue will probably have to trigger the use of \Drupal\Core\Plugin\PreviewAwarePluginInterface — because some blocks only render at all in specific contexts — for example: the messages block is only visible at all when there's actual messages.

See \Drupal\layout_builder\EventSubscriber\BlockComponentRenderArray::onBuildRender() (see also how that uses \Drupal\Core\Render\PreviewFallbackInterface), introduced in #3027653: Allow block and layout plugins to determine if they are being previewed → and CR at https://www.drupal.org/node/3272267 → . Note that this will also require core changes, because not all crucial block plugins implement that interface, which is why 🐛 Can't manage Status Messages block in Layout Builder Needs work still exists.

This also relates to 📌 [later phase] ApiPreviewController must use the previewed route's controller, and override canonical content entity routes' received entity object Postponed , because without that, the preview will not be accurate. Hopefully we can do that at a later time, though.

Wim, this is all extremely valuable to be aware of, thank you! I wonder, though, if we could keep this issue smaller and only focus on the UX and UI aspects of focusing the regions. We have all the pieces in place to make that happen in a smaller scope — in favor of progress. What do you think?

Also, what are we missing in terms of design? I linked to the relevant part of the Figma project, and also added a screenshot.

Okay, I'll extract #3 into a separate issue.

The designs do not provide answers for the highly dynamic Block-sourced Components: it assumes all component instances in the panel are always visible. That's not true for many Block plugins:

• messages block
• local tasks block
• local actions block
• …

But I'm fine with this issue focusing on that tighter scope.

The designs do not provide answers for the highly dynamic Block-sourced Components: it assumes all component instances in the Layers panel are always visible.

Okay, that definitely does need design in the follow-up issue. 🙂 Thanks for agreeing to that.

I would argue though that one thing is missing from the design: the ability to view and edit the PageTemplate in the context of a particular route. That's what 📌 [later phase] ApiPreviewController must use the previewed route's controller, and override canonical content entity routes' received entity object Postponed is about.

… but let's be pragmatic and do only what the design currently covers.

Follow-up for #3 created as requested in #4: 🐛 [Needs design] Previews of pages containing (dynamically) empty blocks are malformed Active .

Per #2, this is blocked on ✨ Show page information in top bar Active , right @balintbrews?

It's not blocked, but at one point some coordination may be required. 😊

Would this issue benefit from automated tests, or would that be disproportionately complex and would this benefit from (documented) manual testing instead?

FYI: this blocks 📌 Implement HTML comment annotations for Regions, replace HTML wrappers Active .

Up until now, the XB team has been following a pseudo-scrum/pseudo-kanban process, but we're now shifting into more conventional scrum. We started a new 2-week sprint last Thursday (Jan 16). I'm tagging our current sprint's issues for visibility.