webui : [ChatFormActionAdd][a11y] fix accessibility issues in add menu trigger and items (#22736)

* fix tab order on attach button, and dont focus on disabled mennu item

* add a11y tests

tools/ui/src/lib/components/app/chat/ChatForm/ChatFormActions/ChatFormActionAdd/ChatFormActionAddDropdown.svelte

@@ -1,11 +1,14 @@
 <script lang="ts">
-	import type { Snippet } from 'svelte';
+	import { Plus } from '@lucide/svelte';
 	import * as DropdownMenu from '$lib/components/ui/dropdown-menu';
 	import * as Tooltip from '$lib/components/ui/tooltip';
+	import { buttonVariants } from '$lib/components/ui/button';
+	import { cn } from '$lib/components/ui/utils';
 	import {
 		ATTACHMENT_FILE_ITEMS,
 		ATTACHMENT_EXTRA_ITEMS,
 		ATTACHMENT_MCP_ITEMS,
+		ATTACHMENT_TOOLTIP_TEXT,
 		TOOLTIP_DELAY_DURATION
 	} from '$lib/constants';
 	import { AttachmentMenuItemId } from '$lib/enums';
@@ -28,7 +31,6 @@
 		onMcpPromptClick?: () => void;
 		onMcpSettingsClick?: () => void;
 		onMcpResourcesClick?: () => void;
-		trigger: Snippet<[{ disabled: boolean }]>;
 	}
 
 	let {
@@ -42,8 +44,7 @@
 		onSystemPromptClick,
 		onMcpPromptClick,
 		onMcpSettingsClick,
-		onMcpResourcesClick,
+		onMcpResourcesClick
-		trigger
 	}: Props = $props();
 
 	let dropdownOpen = $state(false);
@@ -69,9 +70,28 @@
 
 <div class="flex items-center gap-1 {className}">
 	<DropdownMenu.Root bind:open={dropdownOpen}>
-		<DropdownMenu.Trigger name="Attach files" {disabled}>
+		<Tooltip.Root>
-			{@render trigger({ disabled })}
+			<Tooltip.Trigger>
+				{#snippet child({ props })}
+					<DropdownMenu.Trigger
+						{...props}
+						class={cn(
+							buttonVariants({ variant: 'secondary' }),
+							'file-upload-button h-8 w-8 cursor-pointer rounded-full p-0'
+						)}
+						{disabled}
+					>
+						<span class="sr-only">{ATTACHMENT_TOOLTIP_TEXT}</span>
+
+						<Plus class="h-4 w-4" />
 					</DropdownMenu.Trigger>
+				{/snippet}
+			</Tooltip.Trigger>
+
+			<Tooltip.Content>
+				<p>{ATTACHMENT_TOOLTIP_TEXT}</p>
+			</Tooltip.Content>
+		</Tooltip.Root>
 
 		<DropdownMenu.Content align="start" class="w-48">
 			{#each ATTACHMENT_FILE_ITEMS as item (item.id)}
@@ -87,15 +107,16 @@
 					</DropdownMenu.Item>
 				{:else if item.disabledTooltip}
 					<Tooltip.Root delayDuration={TOOLTIP_DELAY_DURATION}>
-						<Tooltip.Trigger class="w-full">
+						<Tooltip.Trigger tabindex={-1}>
-							<DropdownMenu.Item
+							{#snippet child({ props })}
-								class="{item.class ?? ''} flex cursor-pointer items-center gap-2"
+								<div {...props} class="cursor-default">
-								disabled
+									<DropdownMenu.Item class="{item.class ?? ''} flex items-center gap-2" disabled>
-							>
 										<item.icon class="h-4 w-4" />
 
 										<span>{item.label}</span>
 									</DropdownMenu.Item>
+								</div>
+							{/snippet}
 						</Tooltip.Trigger>
 
 						<Tooltip.Content side="right">
@@ -107,8 +128,10 @@
 
 			{#if !attachmentMenu.isItemEnabled('hasVisionModality')}
 				<Tooltip.Root delayDuration={TOOLTIP_DELAY_DURATION}>
-					<Tooltip.Trigger class="w-full">
+					<Tooltip.Trigger>
+						{#snippet child({ props })}
 							<DropdownMenu.Item
+								{...props}
 								class="flex cursor-pointer items-center gap-2"
 								onclick={attachmentMenu.callbacks.onFileUpload}
 							>
@@ -121,6 +144,7 @@
 									<span>{pdfItem.label}</span>
 								{/if}
 							</DropdownMenu.Item>
+						{/snippet}
 					</Tooltip.Trigger>
 
 					<Tooltip.Content side="right">
@@ -134,8 +158,10 @@
 			{#each ATTACHMENT_EXTRA_ITEMS as item (item.id)}
 				{#if item.id === AttachmentMenuItemId.SYSTEM_MESSAGE}
 					<Tooltip.Root delayDuration={TOOLTIP_DELAY_DURATION}>
-						<Tooltip.Trigger class="w-full">
+						<Tooltip.Trigger>
+							{#snippet child({ props })}
 								<DropdownMenu.Item
+									{...props}
 									class="flex cursor-pointer items-center gap-2"
 									onclick={() => attachmentMenu.callbacks[item.action]()}
 								>
@@ -143,6 +169,7 @@
 
 									<span>{item.label}</span>
 								</DropdownMenu.Item>
+							{/snippet}
 						</Tooltip.Trigger>
 
 						<Tooltip.Content side="right">

tools/ui/src/lib/components/app/chat/ChatForm/ChatFormActions/ChatFormActionAdd/ChatFormActionsAdd.svelte

@@ -60,9 +60,5 @@
 		{onMcpResourcesClick}
 		{onMcpSettingsClick}
 		{onSystemPromptClick}
-	>
+	/>
-		{#snippet trigger()}
-			<ChatFormActionAddButton {disabled} />
-		{/snippet}
-	</ChatFormActionAddDropdown>
 {/if}

tools/ui/tests/stories/ChatScreenForm.a11y.stories.svelte

@@ -0,0 +1,50 @@
+<script module lang="ts">
+	import { defineMeta } from '@storybook/addon-svelte-csf';
+	import ChatScreenForm from '$lib/components/app/chat/ChatScreen/ChatScreenForm.svelte';
+	import { expect, screen, waitFor } from 'storybook/test';
+	import { ATTACHMENT_TOOLTIP_TEXT } from '$lib/constants';
+
+	const { Story } = defineMeta({
+		title: 'Components/ChatScreen/ChatScreenForm/Accessibility',
+		component: ChatScreenForm,
+		parameters: {
+			layout: 'centered'
+		},
+		tags: ['!dev']
+	});
+</script>
+
+<Story
+	name="AddButtonSingleTabStop"
+	args={{ class: 'max-w-[56rem] w-[calc(100vw-2rem)]' }}
+	play={async ({ canvas, userEvent }) => {
+		const textarea = await canvas.findByRole('textbox');
+		await userEvent.clear(textarea);
+		await userEvent.type(textarea, 'What is the meaning of life?');
+
+		const trigger = await canvas.findByRole('button', { name: ATTACHMENT_TOOLTIP_TEXT });
+
+		trigger.focus();
+		await expect(trigger).toHaveFocus();
+
+		await userEvent.tab();
+
+		await expect(trigger).not.toHaveFocus();
+	}}
+/>
+
+<Story
+	name="AddDropdownFocusesFirstEnabled"
+	args={{ class: 'max-w-[56rem] w-[calc(100vw-2rem)]' }}
+	play={async ({ canvas, userEvent }) => {
+		const trigger = await canvas.findByRole('button', { name: ATTACHMENT_TOOLTIP_TEXT });
+
+		trigger.focus();
+		await userEvent.keyboard('{Enter}');
+		await screen.findByRole('menu');
+
+		await waitFor(() => {
+			expect(document.activeElement).toHaveTextContent('Text Files');
+		});
+	}}
+/>