Reveal the selected item when cycling a picker's selection (#12950)

Release Notes:

- Fixed a bug where the selected tab was not always shown when cycling
between tabs with `ctrl-tab`.

crates/picker/Cargo.toml

@@ -12,6 +12,9 @@ workspace = true
 path = "src/picker.rs"
 doctest = false
 
+[features]
+test-support = []
+
 [dependencies]
 anyhow.workspace = true
 editor.workspace = true

crates/picker/src/picker.rs

@@ -310,7 +310,7 @@ impl<D: PickerDelegate> Picker<D> {
         let count = self.delegate.match_count();
         let index = self.delegate.selected_index();
         let new_index = if index + 1 == count { 0 } else { index + 1 };
-        self.set_selected_index(new_index, false, cx);
+        self.set_selected_index(new_index, true, cx);
         cx.notify();
     }
 
@@ -538,6 +538,16 @@ impl<D: PickerDelegate> Picker<D> {
                 .into_any_element(),
         }
     }
+
+    #[cfg(any(test, feature = "test-support"))]
+    pub fn logical_scroll_top_index(&self) -> usize {
+        match &self.element_container {
+            ElementContainer::List(state) => state.logical_scroll_top().item_ix,
+            ElementContainer::UniformList(scroll_handle) => {
+                scroll_handle.logical_scroll_top_index()
+            }
+        }
+    }
 }
 
 impl<D: PickerDelegate> EventEmitter<DismissEvent> for Picker<D> {}