dock: Add tab_name for collapsed tab panels (#751)

crates/ui/src/dock/panel.rs

@@ -59,6 +59,13 @@ pub trait Panel: EventEmitter<PanelEvent> + Render + Focusable {
     /// Once you have defined a panel name, this must not be changed.
     fn panel_name(&self) -> &'static str;
 
+    /// The name of the tab of the panel, default is `None`.
+    ///
+    /// Used to display in the already collapsed tab panel.
+    fn tab_name(&self, cx: &App) -> Option<SharedString> {
+        None
+    }
+
     /// The title of the panel
     fn title(&self, window: &Window, cx: &App) -> AnyElement {
         SharedString::from(t!("Dock.Unnamed")).into_any_element()
@@ -137,6 +144,7 @@ pub trait Panel: EventEmitter<PanelEvent> + Render + Focusable {
 pub trait PanelView: 'static + Send + Sync {
     fn panel_name(&self, cx: &App) -> &'static str;
     fn panel_id(&self, cx: &App) -> EntityId;
+    fn tab_name(&self, cx: &App) -> Option<SharedString>;
     fn title(&self, window: &Window, cx: &App) -> AnyElement;
     fn title_suffix(&self, window: &mut Window, cx: &mut App) -> Option<AnyElement>;
     fn title_style(&self, cx: &App) -> Option<TitleStyle>;
@@ -162,6 +170,10 @@ impl<T: Panel> PanelView for Entity<T> {
         self.entity_id()
     }
 
+    fn tab_name(&self, cx: &App) -> Option<SharedString> {
+        self.read(cx).tab_name(cx)
+    }
+
     fn title(&self, window: &Window, cx: &App) -> AnyElement {
         self.read(cx).title(window, cx)
     }

crates/ui/src/dock/tab_panel.rs

@@ -691,7 +691,13 @@ impl TabPanel {
 
                 Some(
                     Tab::new("")
-                        .child(panel.title(window, cx))
+                        .map(|this| {
+                            if let Some(tab_name) = panel.tab_name(cx) {
+                                this.child(tab_name)
+                            } else {
+                                this.child(panel.title(window, cx))
+                            }
+                        })
                         .py_2()
                         .selected(active)
                         .disabled(disabled)