dock: Make the panel inner padding controllable (#613)

crates/ui/src/dock/panel.rs

@@ -119,6 +119,11 @@ pub trait Panel: EventEmitter<PanelEvent> + Render + Focusable {
     fn dump(&self, cx: &App) -> PanelState {
         PanelState::new(self)
     }
+
+    /// Whether the panel has inner padding when the panel is in the tabs layout, default is `true`.
+    fn inner_padding(&self, cx: &App) -> bool {
+        true
+    }
 }
 
 /// The PanelView trait used to define the panel view.
@@ -137,6 +142,7 @@ pub trait PanelView: 'static + Send + Sync {
     fn view(&self) -> AnyView;
     fn focus_handle(&self, cx: &App) -> FocusHandle;
     fn dump(&self, cx: &App) -> PanelState;
+    fn inner_padding(&self, cx: &App) -> bool;
 }
 
 impl<T: Panel> PanelView for Entity<T> {
@@ -195,6 +201,10 @@ impl<T: Panel> PanelView for Entity<T> {
     fn dump(&self, cx: &App) -> PanelState {
         self.read(cx).dump(cx)
     }
+
+    fn inner_padding(&self, cx: &App) -> bool {
+        self.read(cx).inner_padding(cx)
+    }
 }
 
 impl From<&dyn PanelView> for AnyView {

crates/ui/src/dock/tab_panel.rs

@@ -131,6 +131,11 @@ impl Panel for TabPanel {
         }
         state
     }
+
+    fn inner_padding(&self, cx: &App) -> bool {
+        self.active_panel(cx)
+            .map_or(true, |panel| panel.inner_padding(cx))
+    }
 }
 
 impl TabPanel {
@@ -761,7 +766,7 @@ impl TabPanel {
             return Empty {}.into_any_element();
         };
 
-        let is_render_in_tabs = self.panels.len() > 1;
+        let is_render_in_tabs = self.panels.len() > 1 && self.inner_padding(cx);
 
         v_flex()
             .id("tab-content")