The same screenshot but the utility pane in flap also has the same sidebar style.

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1. Alexander Mikhaylenko (alexm@neurodifferent.me)'s status on Tuesday, 07-Mar-2023 04:34:36 JST Alexander Mikhaylenko

   in reply to

   The next widget to replace after leaflet is AdwFlap. And this one is complicated.

   With leaflet: adaptive states, AdwBrowsingView and AdwDualPane view cover most cases - and those that they don't are easily reimplementable in apps, like three-pane layouts.

   With flap it's harder as there are quite a lot of different use cases with it.

   The "fullscreen header bar" case is covered by AdwToolbarView, so that's fine.

   Utility panes can be covered by a new widget made specifically for those.

   There are a few apps using flaps in really creative ways, like Apostrophe - those are gonna have to do it in tree instead. :/

   But one case that's rather surprising is using them as a sidebar, with split header bars and everything. Technically this can work just fine - I mean it's still a generic widget that doesn't care where your header bars are - you won't get anything fancy like window button integration, but otherwise no problems. However, the styles will be wrong - utility panes don't get the new sidebar style.

   Now that's another point I'm not super happy with, so me and Tobias looked at styles to check if maybe utility panes can use the new styles too? And - well, they can. Just not when folded, but AdwDualPaneView also doesn't do it when folded.

   And at this point I become kinda unsure - why is it 2 separate widgets. Because while sidebars and utility panes are indeed separate patterns in the HIG, the line between them is quite blurry.

   From the HIG pov the main difference is whether the header bars are split or not. But that is not an inherent property of either widget, it's just how you use them.

   Besides, for apps like Nautilus we'll likely want it to be sidebar on desktop and turn into a utility pane when folded. This is perfectly possible with adaptive states, but not trivial.

   And then - a difference is whether it changes into browsing when folded, or into a transient sidebar.