Move focus between form fields with tab

src/app.rs

@@ -133,6 +133,10 @@ pub(crate) enum Message {
     WindowOpened(window::Id),
     WindowClosed(window::Id),
     DismissPanel,
+    /// Tab and shift-tab: iced leaves the key to the application, so the fields
+    /// of a form are only linked once we move the focus ourselves.
+    FocusNext,
+    FocusPrevious,
     PreferenceModelChanged(ModelChoice),
     PreferenceDsparkChanged(bool),
     PreferenceTimeoutChanged(String),
@@ -447,6 +451,8 @@ impl App {
                     self.error = None;
                 }
             }
+            Message::FocusNext => return iced::widget::focus_next(),
+            Message::FocusPrevious => return iced::widget::focus_previous(),
             Message::ShowChat => self.detail_tab = DetailTab::Chat,
             Message::ShowStats => {
                 self.detail_tab = DetailTab::Stats;
@@ -1200,6 +1206,11 @@ fn shortcut(key: keyboard::Key, modifiers: keyboard::Modifiers) -> Option<Messag
             Some(Message::OpenModelManager)
         }
         keyboard::Key::Named(keyboard::key::Named::Escape) => Some(Message::DismissPanel),
+        keyboard::Key::Named(keyboard::key::Named::Tab) => Some(if modifiers.shift() {
+            Message::FocusPrevious
+        } else {
+            Message::FocusNext
+        }),
         _ => None,
     }
 }
@@ -1318,6 +1329,15 @@ mod tests {
             keyboard::Modifiers::COMMAND | keyboard::Modifiers::SHIFT,
         );
         assert!(matches!(message, Some(Message::OpenModelManager)));
+        let tab = keyboard::Key::Named(keyboard::key::Named::Tab);
+        assert!(matches!(
+            shortcut(tab.clone(), keyboard::Modifiers::empty()),
+            Some(Message::FocusNext)
+        ));
+        assert!(matches!(
+            shortcut(tab, keyboard::Modifiers::SHIFT),
+            Some(Message::FocusPrevious)
+        ));
         assert!(ModelChoice::DeepSeekV4Flash.supports_dspark());
         assert!(!ModelChoice::DeepSeekV4Pro.supports_dspark());
         assert!(!ModelChoice::Glm52.supports_dspark());