fix: make first item focusable when selected is negative (#7574) (#7575)

Co-authored-by: Serhii Kulykov <[email protected]>

packages/a11y-base/src/list-mixin.js

@@ -166,7 +166,8 @@ export const ListMixin = (superClass) =>
             }
           });
 
-          this._setFocusable(selected || 0);
+          // When selected is set to -1, focus the first available item.
+          this._setFocusable(selected < 0 || !selected ? 0 : selected);
 
           const itemToSelect = items[selected];
           items.forEach((item) => {

packages/a11y-base/test/list-mixin.test.js

@@ -269,6 +269,12 @@ const runTests = (defineHelper, baseMixin) => {
       [-1, -1, 0, -1].forEach((val, idx) => expect(list.items[idx].tabIndex).to.equal(val));
     });
 
+    it('should have the first not disabled item focusable when selected set to -1', async () => {
+      list.selected = -1;
+      await nextUpdate(list);
+      [-1, -1, 0, -1].forEach((val, idx) => expect(list.items[idx].tabIndex).to.equal(val));
+    });
+
     it('should set a not disabled item focusable', async () => {
       list._setFocusable(3);
       await nextUpdate(list);