fix: place AutoSum caret inside empty formula

crates/ui-egui/src/app/commands.rs

@@ -52,6 +52,15 @@ impl SheetApp {
         // Requests the command made (a dialog, a draft) belong to the window it left active.
         self.follow_active_window();
         self.after_engine();
+        if id == "formulas.autoSum"
+            && let Some(ed) = self.editor.as_mut()
+            && ed.text.starts_with('=')
+            && ed.text.ends_with("()")
+        {
+            ed.caret = ed.text.chars().count().saturating_sub(1);
+            ed.anchor = ed.caret;
+            ed.sync_caret = true;
+        }
         if id == "view.arrangeAll"
             && self.native_windows
             && let Ok(r) = &r

crates/ui-egui/tests/it/formula_locale.rs

@@ -140,6 +140,15 @@ fn locale_preserves_text_cells_and_existing_entry_conveniences() {
     assert_eq!(app.editor.as_ref().unwrap().text, "=SUM(1,2)");
 }
 
+#[test]
+fn empty_cell_autosum_places_caret_inside_parentheses() {
+    let mut app = app();
+    app.run("formulas.autoSum", json!({"enter": false})).unwrap();
+    let ed = app.editor.as_ref().unwrap();
+    assert_eq!(ed.text, "=SUM()");
+    assert_eq!(ed.caret, ed.text.chars().count() - 1);
+}
+
 #[test]
 /// Insert Function and AutoSum use `=SUMA(`, while user-supplied formula text is not translated twice.
 fn canonical_engine_templates_enter_the_selected_formula_language() {