improved activation/deactivation for input panel

src/inspect_ai/_display/textual/app.py

@@ -351,18 +351,30 @@ def set_title(self, title: str) -> None:
             tab.label = Text.from_markup(title)
 
         def activate(self) -> None:
+            # show the tab
             tabs = self.app.query_one(TabbedContent)
             tabs.show_tab(self.tab_id)
 
+            # focus the first focuable child (this seems to be necessary
+            # to get textual to reliably make the switch). after that, focus
+            # the tabs control so the user can switch back w/ the keyboard
+            tab_pane = self.app.query_one(f"#{self.tab_id}")
+            panel = cast(InputPanel, tab_pane.children[0])
+            for child in panel.children:
+                if child.focusable:
+                    child.focus()
+                    self.app.query_one(ContentTabs).focus()
+                    break
+
         def deactivate(self) -> None:
             tabs = self.app.query_one(TabbedContent)
             if tabs.active == self.tab_id:
                 self.app.activate_tasks_tab()
 
         def close(self) -> None:
-            self.app.activate_tasks_tab()
             tabs = self.app.query_one(TabbedContent)
             tabs.remove_pane(self.tab_id)
+            self.app.activate_tasks_tab()
 
 
 class TextualTaskScreen(TaskScreen, Generic[TR]):

src/inspect_ai/util/_panel.py

@@ -60,6 +60,22 @@ async def input_panel(title: str, panel: type[TP]) -> TP:
     'title' running at once. Therefore, if the panel doesn't exist it
     is created, otherwise a reference to the existing panel is returned.
 
+    Examples:
+        Create/activate an input panel (the panel will remain after
+        the scope exits -- see below for open/close semantics)
+
+        ```python
+        panel = await input_panel("Custom", CustomPanel)
+        panel.activate()
+        ```
+
+        Activate and close an input panel using a context manager:
+
+        ```python
+        async with await input_panel("Custom", CustomPanel) as panel:
+            ...
+        ```
+
     Args:
        title (str): Input panel title.
        panel (type[TP]): Type of panel widget (must derive from `InputPanel`)