multibuffer: Make "Open File" button also visible on hover (#49980)

Danilo Leal created 1 month ago

This makes the "Open File" button in the file header within multibuffers
also visible as you hover over the headers. Previously, this button
would only show up for the selected/focused file, but it now also shows
up on hover for making mouse-based interaction easier.

Release Notes:

- N/A

Change summary

crates/editor/src/element.rs | 54 +++++++++++++++++++++----------------
1 file changed, 30 insertions(+), 24 deletions(-)

Detailed changes

crates/editor/src/element.rs

@@ -8139,6 +8139,7 @@ pub(crate) fn render_buffer_header(
         .h(FILE_HEADER_HEIGHT as f32 * window.line_height())
         .child(
             h_flex()
+                .group("buffer-header-group")
                 .size_full()
                 .flex_basis(Length::Definite(DefiniteLength::Fraction(0.667)))
                 .pl_1()
@@ -8332,31 +8333,36 @@ pub(crate) fn render_buffer_header(
                                     })
                             },
                         ))
-                        .when(
-                            can_open_excerpts && is_selected && relative_path.is_some(),
-                            |el| {
-                                el.child(
-                                    Button::new("open-file-button", "Open File")
-                                        .style(ButtonStyle::OutlinedGhost)
-                                        .key_binding(KeyBinding::for_action_in(
-                                            &OpenExcerpts,
-                                            &focus_handle,
-                                            cx,
-                                        ))
-                                        .on_click(window.listener_for(editor, {
-                                            let jump_data = jump_data.clone();
-                                            move |editor, e: &ClickEvent, window, cx| {
-                                                editor.open_excerpts_common(
-                                                    Some(jump_data.clone()),
-                                                    e.modifiers().secondary(),
-                                                    window,
+                        .when(can_open_excerpts && relative_path.is_some(), |this| {
+                            this.child(
+                                div()
+                                    .when(!is_selected, |this| {
+                                        this.visible_on_hover("buffer-header-group")
+                                    })
+                                    .child(
+                                        Button::new("open-file-button", "Open File")
+                                            .style(ButtonStyle::OutlinedGhost)
+                                            .when(is_selected, |this| {
+                                                this.key_binding(KeyBinding::for_action_in(
+                                                    &OpenExcerpts,
+                                                    &focus_handle,
                                                     cx,
-                                                );
-                                            }
-                                        })),
-                                )
-                            },
-                        )
+                                                ))
+                                            })
+                                            .on_click(window.listener_for(editor, {
+                                                let jump_data = jump_data.clone();
+                                                move |editor, e: &ClickEvent, window, cx| {
+                                                    editor.open_excerpts_common(
+                                                        Some(jump_data.clone()),
+                                                        e.modifiers().secondary(),
+                                                        window,
+                                                        cx,
+                                                    );
+                                                }
+                                            })),
+                                    ),
+                            )
+                        })
                         .on_mouse_down(MouseButton::Left, |_, _, cx| cx.stop_propagation())
                         .on_click(window.listener_for(editor, {
                             let buffer_id = for_excerpt.buffer_id;