[FIX] topbar: close font size dropdown and keep focus on the grid

Pressing Tab in the font size editor could move focus to the hidden
“add more rows” footer. The browser then auto-scrolled to that footer
while the grid viewport state stayed unchanged, making the footer look
like it was floating above the grid.

We now handle Tab on the font size input: we prevent the default
navigation, close the dropdown, and redirect focus back to the grid
composer instead of the footer. This keeps the layout stable when
tabbing from the toolbar.

Alternative approaches considered but discarded:

- Closing on blur and refocusing the grid: clicking the arrow caused
  the input to blur first, so the blur handler closed the dropdown and
  the arrow click immediately reopened it, making it impossible to
  close the dropdown.
- Using mousedown to distinguish internal clicks: this fired before
  selecting an item in the dropdown, so the dropdown closed too early
  and the item click was never applied.

Task: 5263792

Author: dhrp-odoo

src/components/font_size_editor/font_size_editor.ts

@@ -1,6 +1,8 @@
 import { Component, useExternalListener, useRef, useState } from "@odoo/owl";
 import { FONT_SIZES } from "../../constants";
 import { clip } from "../../helpers/index";
+import { Store, useStore } from "../../store_engine";
+import { DOMFocusableElementStore } from "../../stores/DOM_focus_store";
 import { SpreadsheetChildEnv } from "../../types/index";
 import { css } from "../helpers/css";
 import { isChildEvent } from "../helpers/dom_helpers";
@@ -62,7 +64,10 @@ export class FontSizeEditor extends Component<Props, SpreadsheetChildEnv> {
   private rootEditorRef = useRef("FontSizeEditor");
   private fontSizeListRef = useRef("fontSizeList");
 
+  private DOMFocusableElementStore!: Store<DOMFocusableElementStore>;
+
   setup() {
+    this.DOMFocusableElementStore = useStore(DOMFocusableElementStore);
     useExternalListener(window, "click", this.onExternalClick, { capture: true });
   }
 
@@ -124,5 +129,12 @@ export class FontSizeEditor extends Component<Props, SpreadsheetChildEnv> {
       }
       this.props.onToggle?.();
     }
+    if (ev.key === "Tab") {
+      ev.preventDefault();
+      ev.stopPropagation();
+      this.closeFontList();
+      this.DOMFocusableElementStore.focus();
+      return;
+    }
   }
 }

src/components/font_size_editor/font_size_editor.xml

@@ -5,7 +5,7 @@
         class=" o-font-size-editor d-flex align-items-center"
         t-att-class="props.class"
         title="Font Size"
-        t-on-click="this.toggleFontList">
+        t-on-click.stop="this.toggleFontList">
         <input
           type="number"
           min="1"

src/components/grid_add_rows_footer/grid_add_rows_footer.xml

@@ -7,7 +7,8 @@
       <button
         t-on-click="onConfirm"
         t-att-disabled="state.errorFlag"
-        class="o-button flex-grow-0 me-2">
+        class="o-button flex-grow-0 me-2"
+        tabindex="-1">
         Add
       </button>
       <input
@@ -19,6 +20,7 @@
         t-on-keydown.stop="onKeydown"
         t-on-pointerdown.stop=""
         t-on-input.stop="onInput"
+        tabindex="-1"
       />
       <span>more rows at the bottom</span>
       <ValidationMessages t-if="state.errorFlag" messages="errorMessages" msgType="'error'"/>

tests/grid/__snapshots__/grid_component.test.ts.snap

@@ -29,11 +29,13 @@ exports[`Grid component simple rendering snapshot 1`] = `
     >
       <button
         class="o-button flex-grow-0 me-2"
+        tabindex="-1"
       >
          Add 
       </button>
       <input
         class="o-grid-add-rows-input o-input mt-0 me-2"
+        tabindex="-1"
         type="text"
         value="100"
       />

tests/spreadsheet/__snapshots__/spreadsheet_component.test.ts.snap

@@ -771,11 +771,13 @@ exports[`Simple Spreadsheet Component simple rendering snapshot 1`] = `
           >
             <button
               class="o-button flex-grow-0 me-2"
+              tabindex="-1"
             >
                Add 
             </button>
             <input
               class="o-grid-add-rows-input o-input mt-0 me-2"
+              tabindex="-1"
               type="text"
               value="100"
             />
@@ -1713,11 +1715,13 @@ exports[`components take the small screen into account 1`] = `
           >
             <button
               class="o-button flex-grow-0 me-2"
+              tabindex="-1"
             >
                Add 
             </button>
             <input
               class="o-grid-add-rows-input o-input mt-0 me-2"
+              tabindex="-1"
               type="text"
               value="100"
             />

tests/top_bar_component.test.ts

@@ -29,6 +29,7 @@ import {
   doubleClick,
   getElComputedStyle,
   getTextNodes,
+  keyDown,
   simulateClick,
   triggerMouseEvent,
 } from "./test_helpers/dom_helper";
@@ -443,6 +444,25 @@ describe("TopBar component", () => {
     expect(getStyle(model, "A1").fontSize).toBe(8);
   });
 
+  test("Tab from font size editor closes the dropdown and moves focus to grid", async () => {
+    const { fixture } = await mountSpreadsheet();
+    const input = fixture.querySelector("input.o-font-size") as HTMLInputElement;
+    input.focus();
+    await nextTick();
+    expect(fixture.querySelector(".o-popover .o-text-options")).toBeTruthy();
+    await keyDown({ key: "Tab" });
+    expect(fixture.querySelector(".o-popover .o-text-options")).toBeFalsy();
+    const composerEl = fixture.querySelector<HTMLElement>(".o-grid-composer .o-composer")!;
+    expect(document.activeElement).toBe(composerEl);
+  });
+
+  test("Clicking the font size dropdown arrow focuses the input", async () => {
+    const { fixture } = await mountSpreadsheet();
+    const input = fixture.querySelector("input.o-font-size") as HTMLInputElement;
+    await click(fixture, ".o-font-size-editor .o-icon");
+    expect(document.activeElement).toBe(input);
+  });
+
   test("prevents default behavior of mouse wheel event on font size input", async () => {
     await mountParent();
     const fontSizeInput = fixture.querySelector("input.o-font-size") as HTMLInputElement;