bezel

Components / Layout & organisation

Collapsible

crates/ui/src/widgets/layout.rs

use ui::widgets;

div()
    .child(
        div()
            .id("collapse")
            .on_click(cx.listener(|view, _, _, cx| {
                view.expanded = !view.expanded;
                cx.notify();
            }))
            .child(widgets::collapsible_header(&theme, "Advanced", self.expanded)),
    )
    .when(self.expanded, |el| el.child(body))

The header is a row, not a container. Swallowing the children would mean re-implementing layout for them, and the body of a collapsible is usually the most layout-specific thing on the page.

widgets::disclosure(&theme, expanded) is the chevron on its own — two assets rather than one rotated, because gpui has no transform for divs at the pinned rev.

When the section should open itself while something runs and close when it stops, Takeover is the flag:

let open = self.details.get(self.running);  // auto until touched
self.details.toggle(self.running);          // the click wins from here

Auto-follow is right until the first press and wrong immediately after — whatever the flag does next, the person who clicked has to win. Nothing agent-shaped about it: a build log that unfolds while it runs and a detail pane that follows the selection both want exactly this.

Collapsible