diff --git a/e2e/timetracker.spec.ts b/e2e/timetracker.spec.ts
index de364e22..caff92cc 100644
--- a/e2e/timetracker.spec.ts
+++ b/e2e/timetracker.spec.ts
@@ -9,7 +9,14 @@ import {
 } from './utils/currentTimeEntry';
 import type { Page } from '@playwright/test';
 import { newTagResponse } from './utils/tags';
-import { createProjectViaApi, updateOrganizationCurrencyViaWeb } from './utils/api';
+import {
+    createProjectViaApi,
+    createTaskViaApi,
+    createClientViaApi,
+    archiveProjectViaApi,
+    markTaskDoneViaApi,
+    updateOrganizationCurrencyViaWeb,
+} from './utils/api';
 
 // Date picker button name patterns for different date formats
 const DATE_DISPLAY_PATTERN = /^\d{4}-\d{2}-\d{2}$|^\d{2}\/\d{2}\/\d{4}$|^\d{2}\.\d{2}\.\d{4}$/;
@@ -441,3 +448,231 @@ test('test that adding a project and tag before starting timer works', async ({
     ]);
     await assertThatTimerIsStopped(page);
 });
+
+// ──────────────────────────────────────────────────
+// Project / Task selector dropdown
+// Regression coverage for the virtualized + lookup-map refactor of
+// TimeTrackerProjectTaskDropdown. The dropdown only (re)filters on open and on search
+// change, so we wait for the dashboard prefetch to settle before opening it.
+// ──────────────────────────────────────────────────
+
+test.describe('Project Task Dropdown', () => {
+    test.describe.configure({ timeout: 60_000 });
+
+    test('test that a project far down a long list can be found via search and selected', async ({
+        page,
+        ctx,
+    }) => {
+        // Seed enough projects that the target sits outside the initially rendered window.
+        const seed = Math.floor(Math.random() * 100000);
+        const prefix = `VirtProj ${seed} `;
+        await Promise.all(
+            Array.from({ length: 30 }, (_, i) =>
+                createProjectViaApi(ctx, { name: prefix + String(i).padStart(2, '0') })
+            )
+        );
+        const target = prefix + '27';
+
+        await goToDashboard(page);
+        await page.waitForLoadState('networkidle');
+
+        await page.getByRole('button', { name: 'No Project' }).click();
+        await page.getByTestId('client_dropdown_search').fill(target);
+        await page.getByRole('option').filter({ hasText: target }).click();
+
+        // The trigger now reflects the selected project.
+        await expect(page.getByRole('button', { name: target })).toBeVisible();
+    });
+
+    test('test that expanding a project and selecting a task works', async ({ page, ctx }) => {
+        const seed = Math.floor(Math.random() * 100000);
+        const projectName = `ExpandProj ${seed}`;
+        const taskName = `ExpandTask ${seed}`;
+        const project = await createProjectViaApi(ctx, { name: projectName });
+        await createTaskViaApi(ctx, { name: taskName, project_id: project.id });
+
+        await goToDashboard(page);
+        await page.waitForLoadState('networkidle');
+
+        await page.getByRole('button', { name: 'No Project' }).click();
+        const projectOption = page.getByRole('option').filter({ hasText: projectName });
+        await expect(projectOption).toBeVisible();
+
+        // Expand the project's tasks via the "N Tasks" button, then select the task.
+        await projectOption.getByText(/Tasks/).click();
+        await page.getByText(taskName, { exact: true }).click();
+
+        // The trigger reflects the selected task.
+        await expect(page.getByText(taskName)).toBeVisible();
+    });
+
+    test('test that keyboard navigation selects a project', async ({ page, ctx }) => {
+        const seed = Math.floor(Math.random() * 100000);
+        const projectName = `KbProj ${seed}`;
+        await createProjectViaApi(ctx, { name: projectName });
+
+        await goToDashboard(page);
+        await page.waitForLoadState('networkidle');
+
+        await page.getByRole('button', { name: 'No Project' }).click();
+        const search = page.getByTestId('client_dropdown_search');
+        // On open the search is focused and "No Project" is highlighted.
+        await expect(search).toBeFocused();
+
+        // Arrow down from "No Project" to the project, then select it with Enter.
+        await search.press('ArrowDown');
+        await search.press('Enter');
+
+        await expect(page.getByRole('button', { name: projectName })).toBeVisible();
+    });
+
+    test('test that search filters the dropdown by project and client name', async ({
+        page,
+        ctx,
+    }) => {
+        const seed = Math.floor(Math.random() * 100000);
+        const clientName = `FilterClient ${seed}`;
+        const alphaProject = `AlphaProj ${seed}`;
+        const betaProject = `BetaProj ${seed}`;
+        const client = await createClientViaApi(ctx, { name: clientName });
+        await createProjectViaApi(ctx, { name: alphaProject, client_id: client.id });
+        await createProjectViaApi(ctx, { name: betaProject });
+
+        await goToDashboard(page);
+        await page.waitForLoadState('networkidle');
+
+        await page.getByRole('button', { name: 'No Project' }).click();
+        const search = page.getByTestId('client_dropdown_search');
+        const alphaOption = page.getByRole('option').filter({ hasText: alphaProject });
+        const betaOption = page.getByRole('option').filter({ hasText: betaProject });
+
+        // Both projects are visible before filtering.
+        await expect(alphaOption).toBeVisible();
+        await expect(betaOption).toBeVisible();
+
+        // Project-name search shows only the matching project.
+        await search.fill('AlphaProj');
+        await expect(alphaOption).toBeVisible();
+        await expect(betaOption).not.toBeVisible();
+
+        // Client-name search shows the project that belongs to that client.
+        await search.fill(clientName);
+        await expect(alphaOption).toBeVisible();
+        await expect(betaOption).not.toBeVisible();
+    });
+
+    test("test that searching by task name surfaces the task's project", async ({ page, ctx }) => {
+        const seed = Math.floor(Math.random() * 100000);
+        const projectWithTask = `TaskSearchProj ${seed}`;
+        const taskName = `Findable Task ${seed}`;
+        const unrelatedProject = `Unrelated Proj ${seed}`;
+        const project = await createProjectViaApi(ctx, { name: projectWithTask });
+        await createTaskViaApi(ctx, { name: taskName, project_id: project.id });
+        await createProjectViaApi(ctx, { name: unrelatedProject });
+
+        await goToDashboard(page);
+        await page.waitForLoadState('networkidle');
+
+        await page.getByRole('button', { name: 'No Project' }).click();
+        await page.getByTestId('client_dropdown_search').fill(taskName);
+
+        // The project owning the task is shown (with the task), the unrelated project is not.
+        await expect(page.getByRole('option').filter({ hasText: projectWithTask })).toBeVisible();
+        await expect(page.getByText(taskName, { exact: true })).toBeVisible();
+        await expect(
+            page.getByRole('option').filter({ hasText: unrelatedProject })
+        ).not.toBeVisible();
+    });
+
+    test('test that archived projects are hidden from the dropdown', async ({ page, ctx }) => {
+        const seed = Math.floor(Math.random() * 100000);
+        const activeProject = `ActiveProj ${seed}`;
+        const archivedProject = `ArchivedProj ${seed}`;
+        await createProjectViaApi(ctx, { name: activeProject });
+        const toArchive = await createProjectViaApi(ctx, { name: archivedProject });
+        await archiveProjectViaApi(ctx, toArchive);
+
+        await goToDashboard(page);
+        await page.waitForLoadState('networkidle');
+
+        await page.getByRole('button', { name: 'No Project' }).click();
+
+        // Wait for the list to load, then confirm the archived project is filtered out.
+        await expect(page.getByRole('option').filter({ hasText: activeProject })).toBeVisible();
+        await expect(
+            page.getByRole('option').filter({ hasText: archivedProject })
+        ).not.toBeVisible();
+    });
+
+    test('test that done tasks are hidden when expanding a project', async ({ page, ctx }) => {
+        const seed = Math.floor(Math.random() * 100000);
+        const projectName = `DoneTaskProj ${seed}`;
+        const activeTask = `Active Task ${seed}`;
+        const doneTask = `Done Task ${seed}`;
+        const project = await createProjectViaApi(ctx, { name: projectName });
+        await createTaskViaApi(ctx, { name: activeTask, project_id: project.id });
+        const taskToFinish = await createTaskViaApi(ctx, {
+            name: doneTask,
+            project_id: project.id,
+        });
+        await markTaskDoneViaApi(ctx, taskToFinish);
+
+        await goToDashboard(page);
+        await page.waitForLoadState('networkidle');
+
+        await page.getByRole('button', { name: 'No Project' }).click();
+        const projectOption = page.getByRole('option').filter({ hasText: projectName });
+        await expect(projectOption).toBeVisible();
+        await projectOption.getByText(/Tasks/).click();
+
+        // Only the active task shows; the done task is filtered out.
+        await expect(page.getByText(activeTask, { exact: true })).toBeVisible();
+        await expect(page.getByText(doneTask, { exact: true })).not.toBeVisible();
+    });
+
+    test('test that keyboard navigation can expand a project and select a task', async ({
+        page,
+        ctx,
+    }) => {
+        const seed = Math.floor(Math.random() * 100000);
+        const projectName = `KbTaskProj ${seed}`;
+        const taskName = `KbTask ${seed}`;
+        const project = await createProjectViaApi(ctx, { name: projectName });
+        await createTaskViaApi(ctx, { name: taskName, project_id: project.id });
+
+        await goToDashboard(page);
+        await page.waitForLoadState('networkidle');
+
+        await page.getByRole('button', { name: 'No Project' }).click();
+        const search = page.getByTestId('client_dropdown_search');
+        await expect(search).toBeFocused();
+
+        // No Project is highlighted on open: down to the project, right to expand its tasks,
+        // down to the task, Enter to select it.
+        await search.press('ArrowDown');
+        await search.press('ArrowRight');
+        await search.press('ArrowDown');
+        await search.press('Enter');
+
+        await expect(page.getByText(taskName)).toBeVisible();
+    });
+
+    test('test that pressing space selects the highlighted project', async ({ page, ctx }) => {
+        const seed = Math.floor(Math.random() * 100000);
+        const projectName = `SpaceProj ${seed}`;
+        await createProjectViaApi(ctx, { name: projectName });
+
+        await goToDashboard(page);
+        await page.waitForLoadState('networkidle');
+
+        await page.getByRole('button', { name: 'No Project' }).click();
+        const search = page.getByTestId('client_dropdown_search');
+        await expect(search).toBeFocused();
+
+        // Arrow down from "No Project" to the project, then the space shortcut selects it.
+        await search.press('ArrowDown');
+        await search.press('Space');
+
+        await expect(page.getByRole('button', { name: projectName })).toBeVisible();
+    });
+});
diff --git a/e2e/utils/api.ts b/e2e/utils/api.ts
index e693529e..62892e6a 100644
--- a/e2e/utils/api.ts
+++ b/e2e/utils/api.ts
@@ -373,6 +373,20 @@ export async function createTaskViaApi(
     return body.data as { id: string; name: string; project_id: string };
 }
 
+export async function markTaskDoneViaApi(ctx: TestContext, task: { id: string; name: string }) {
+    const response = await ctx.request.put(
+        `${PLAYWRIGHT_BASE_URL}/api/v1/organizations/${ctx.orgId}/tasks/${task.id}`,
+        {
+            data: {
+                name: task.name,
+                is_done: true,
+            },
+        }
+    );
+    expect(response.status()).toBe(200);
+    return (await response.json()).data;
+}
+
 export async function createTagViaApi(ctx: TestContext, data: { name: string }) {
     const response = await ctx.request.post(
         `${PLAYWRIGHT_BASE_URL}/api/v1/organizations/${ctx.orgId}/tags`,
diff --git a/package-lock.json b/package-lock.json
index 41172b9e..ea6c8f78 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -20,6 +20,7 @@
                 "@tanstack/vue-query": "^5.100.10",
                 "@tanstack/vue-query-devtools": "^5.91.0",
                 "@tanstack/vue-table": "^8.21.3",
+                "@tanstack/vue-virtual": "^3.13.24",
                 "@vue/eslint-config-prettier": "^10.2.0",
                 "@vue/eslint-config-typescript": "^14.7.0",
                 "@vueuse/core": "^14.3.0",
@@ -5464,17 +5465,6 @@
                 "yallist": "^3.0.2"
             }
         },
-        "node_modules/lucide-vue-next": {
-            "version": "1.0.0",
-            "resolved": "https://registry.npmjs.org/lucide-vue-next/-/lucide-vue-next-1.0.0.tgz",
-            "integrity": "sha512-V6SPvx1IHTj/UY+FrIYWV5faISsPSb8BnWSFDxAtezWKvWc9ZZ40PDrdu1/Qb5vg4lHWr1hs1BAMGVGm6V1Xdg==",
-            "deprecated": "Package deprecated. Please use @lucide/vue instead.",
-            "license": "ISC",
-            "peer": true,
-            "peerDependencies": {
-                "vue": ">=3.0.1"
-            }
-        },
         "node_modules/magic-string": {
             "version": "0.30.21",
             "resolved": "https://registry.npmjs.org/magic-string/-/magic-string-0.30.21.tgz",
@@ -8409,7 +8399,7 @@
             "version": "0.0.6",
             "license": "AGPL-3.0",
             "devDependencies": {
-                "vite-plugin-dts": "^4.0.3"
+                "vite-plugin-dts": "^4.5.4"
             },
             "peerDependencies": {
                 "@zodios/core": "^10.9.6",
@@ -8424,15 +8414,17 @@
             "version": "0.0.21",
             "license": "AGPL-3.0",
             "devDependencies": {
-                "@types/chroma-js": "^3.1.0",
+                "@types/chroma-js": "^3.1.2",
                 "@zodios/core": "^10.9.6",
-                "vite-plugin-dts": "^4.0.3",
-                "zod": "^3.23.8"
+                "vite-plugin-dts": "^4.5.4",
+                "zod": "^3.25.76"
             },
             "peerDependencies": {
                 "@floating-ui/vue": "^1.1.4",
                 "@heroicons/vue": "^2.1.5",
                 "@internationalized/date": "^3.0.0",
+                "@lucide/vue": ">=1.0.0",
+                "@tanstack/vue-virtual": "^3.13.24",
                 "@vitejs/plugin-vue": "^5.1.2 || ^6.0.0",
                 "@vueuse/core": "^12.5.0 || ^14.0.0",
                 "@vueuse/integrations": "^12.5.0 || ^14.0.0",
@@ -8441,7 +8433,6 @@
                 "clsx": "^2.1.1",
                 "dayjs": "^1.11.13",
                 "focus-trap": "^7.0.0 || ^8.0.0",
-                "lucide-vue-next": ">=0.453.0",
                 "parse-duration": "^2.0.1",
                 "radix-vue": "^1.9.0",
                 "reka-ui": "^2.2.0",
diff --git a/package.json b/package.json
index d6c4154d..5bf06dd8 100644
--- a/package.json
+++ b/package.json
@@ -64,6 +64,7 @@
         "@tanstack/vue-query": "^5.100.10",
         "@tanstack/vue-query-devtools": "^5.91.0",
         "@tanstack/vue-table": "^8.21.3",
+        "@tanstack/vue-virtual": "^3.13.24",
         "@vue/eslint-config-prettier": "^10.2.0",
         "@vue/eslint-config-typescript": "^14.7.0",
         "@vueuse/core": "^14.3.0",
diff --git a/resources/js/packages/ui/package.json b/resources/js/packages/ui/package.json
index 6cba9380..068048bd 100644
--- a/resources/js/packages/ui/package.json
+++ b/resources/js/packages/ui/package.json
@@ -57,6 +57,7 @@
         "@floating-ui/vue": "^1.1.4",
         "@heroicons/vue": "^2.1.5",
         "@vitejs/plugin-vue": "^5.1.2 || ^6.0.0",
+        "@tanstack/vue-virtual": "^3.13.24",
         "@vueuse/core": "^12.5.0 || ^14.0.0",
         "@vueuse/integrations": "^12.5.0 || ^14.0.0",
         "focus-trap": "^7.0.0 || ^8.0.0",
diff --git a/resources/js/packages/ui/src/Project/ProjectDropdownItem.vue b/resources/js/packages/ui/src/Project/ProjectDropdownItem.vue
index 22871787..be541f8f 100644
--- a/resources/js/packages/ui/src/Project/ProjectDropdownItem.vue
+++ b/resources/js/packages/ui/src/Project/ProjectDropdownItem.vue
@@ -9,9 +9,9 @@ defineProps<{
 <template>
     <div
         class="flex justify-between items-center w-full text-start text-sm font-medium leading-5 text-text-primary hover:bg-card-background-active focus:outline-none focus:bg-card-background-active transition duration-150 ease-in-out">
-        <div class="flex space-x-3 items-center px-3 py-1.5">
-            <div :style="{ backgroundColor: color }" class="w-3 h-3 rounded-full"></div>
-            <span>{{ name }}</span>
+        <div class="flex space-x-3 items-center px-3 py-1.5 min-w-0">
+            <div :style="{ backgroundColor: color }" class="w-3 h-3 rounded-full shrink-0"></div>
+            <span class="truncate">{{ name }}</span>
         </div>
         <slot name="actions"></slot>
     </div>
diff --git a/resources/js/packages/ui/src/TimeTracker/TimeTrackerProjectTaskDropdown.vue b/resources/js/packages/ui/src/TimeTracker/TimeTrackerProjectTaskDropdown.vue
index 52f19632..9238a5be 100644
--- a/resources/js/packages/ui/src/TimeTracker/TimeTrackerProjectTaskDropdown.vue
+++ b/resources/js/packages/ui/src/TimeTracker/TimeTrackerProjectTaskDropdown.vue
@@ -2,6 +2,7 @@
 import { ChevronRightIcon, ChevronDownIcon } from '@heroicons/vue/16/solid';
 import Dropdown from '@/packages/ui/src/Input/Dropdown.vue';
 import { computed, nextTick, ref, watch } from 'vue';
+import { useVirtualizer } from '@tanstack/vue-virtual';
 import ProjectDropdownItem from '@/packages/ui/src/Project/ProjectDropdownItem.vue';
 import type {
     CreateClientBody,
@@ -85,72 +86,123 @@ const filteredProjects = computed<ProjectWithTasks[]>(() => {
     return filteredResults.value.map((client) => client.projects).flat();
 });
 
+type FlatRow =
+    | { kind: 'client'; key: string; name: string }
+    | { kind: 'project'; key: string; project: ProjectWithTasks }
+    | { kind: 'task'; key: string; task: Task };
+
+// Flatten the grouped client → project → task tree into a single ordered list so it can be
+// virtualized: only the rows currently inside the viewport are mounted, which keeps the
+// dropdown responsive even with thousands of projects/tasks.
+const flatRows = computed<FlatRow[]>(() => {
+    const rows: FlatRow[] = [];
+    for (const client of filteredResults.value) {
+        // The "No Project" group renders its project inline without a client header.
+        if (client.id !== 'no_project_no_client') {
+            rows.push({ kind: 'client', key: 'client-' + client.id, name: client.name });
+        }
+        for (const projectWithTasks of client.projects) {
+            rows.push({
+                kind: 'project',
+                key: 'project-' + projectWithTasks.id,
+                project: projectWithTasks,
+            });
+            if (projectWithTasks.expanded) {
+                for (const taskItem of projectWithTasks.tasks) {
+                    rows.push({ kind: 'task', key: 'task-' + taskItem.id, task: taskItem });
+                }
+            }
+        }
+    }
+    return rows;
+});
+
+const rowVirtualizer = useVirtualizer(
+    computed(() => ({
+        count: flatRows.value.length,
+        getScrollElement: () => dropdownViewport.value,
+        estimateSize: (index: number) => {
+            const row = flatRows.value[index];
+            if (row?.kind === 'client') return 28;
+            if (row?.kind === 'task') return 32;
+            return 38;
+        },
+        getItemKey: (index: number) => flatRows.value[index]?.key ?? index,
+        overscan: 12,
+    }))
+);
+
+const totalSize = computed(() => rowVirtualizer.value.getTotalSize());
+
+const visibleRows = computed(() =>
+    rowVirtualizer.value.getVirtualItems().map((virtualRow) => ({
+        virtualRow,
+        row: flatRows.value[virtualRow.index]!,
+    }))
+);
+
+function measureRow(el: unknown): void {
+    if (el instanceof HTMLElement) {
+        rowVirtualizer.value.measureElement(el);
+    }
+}
+
+// Lookup maps so filtering is O(projects + tasks + clients) instead of
+// O(projects × (tasks + clients)). They are rebuilt only when the underlying task/client
+// props change, not on every keystroke.
+const tasksByProject = computed(() => {
+    const map = new Map<string, Task[]>();
+    for (const taskItem of props.tasks) {
+        const list = map.get(taskItem.project_id);
+        if (list) {
+            list.push(taskItem);
+        } else {
+            map.set(taskItem.project_id, [taskItem]);
+        }
+    }
+    return map;
+});
+
+const clientsById = computed(() => {
+    const map = new Map<string, Client>();
+    for (const clientItem of props.clients) {
+        map.set(clientItem.id, clientItem);
+    }
+    return map;
+});
+
 function addProjectToFilterObject(
     tempFilteredClients: ClientsWithProjectsWithTasks,
+    groupIndexByKey: Map<string, number>,
     project: Project,
     filteredTasks: Task[],
     expanded = false
 ) {
-    // check if client already exists in filter array
-    const projectClientIndex = tempFilteredClients.findIndex(
-        (client) => client.id === project.client_id
-    );
+    const client = project.client_id ? clientsById.value.get(project.client_id) : undefined;
+    const groupKey = client ? client.id : 'no_client';
+    const newProject: ProjectWithTasks = { ...project, expanded, tasks: filteredTasks };
 
-    const client = props.clients.find((client) => client.id === project.client_id);
+    // O(1) group lookup instead of scanning the accumulating array for every project.
+    const existingIndex = groupIndexByKey.get(groupKey);
+    if (existingIndex !== undefined) {
+        tempFilteredClients[existingIndex]!.projects.push(newProject);
+        return;
+    }
 
-    if (projectClientIndex !== -1) {
-        // client already exists in filter array
-        tempFilteredClients[projectClientIndex]!.projects.push({
-            ...project,
-            expanded: expanded,
-            tasks: filteredTasks,
-        });
-    } else if (client) {
-        // project has client but is not already in filter array
-        // client is not yet in filter array
-        tempFilteredClients.push({
-            ...client,
-            projects: [
-                {
-                    ...project,
-                    expanded: expanded,
-                    tasks: filteredTasks,
-                },
-            ],
-        });
+    groupIndexByKey.set(groupKey, tempFilteredClients.length);
+    if (client) {
+        tempFilteredClients.push({ ...client, projects: [newProject] });
     } else {
-        // project has no client
-        const customNoClientId = 'no_client';
-        const noClientIndex = tempFilteredClients.findIndex(
-            (client) => client.id === customNoClientId
-        );
-
-        if (noClientIndex !== -1) {
-            // no client group already exists in filter array
-            tempFilteredClients[noClientIndex]!.projects.push({
-                ...project,
-                expanded: expanded,
-                tasks: filteredTasks,
-            });
-        } else {
-            // no client group is not yet in filter array
-            tempFilteredClients.push({
-                id: customNoClientId,
-                name: 'No Client',
-                color: 'var(--theme-color-icon-default)',
-                created_at: '',
-                updated_at: '',
-                value: '',
-                is_archived: false,
-                projects: [
-                    {
-                        ...project,
-                        expanded: expanded,
-                        tasks: filteredTasks,
-                    },
-                ],
-            });
-        }
+        tempFilteredClients.push({
+            id: 'no_client',
+            name: 'No Client',
+            color: 'var(--theme-color-icon-default)',
+            created_at: '',
+            updated_at: '',
+            value: '',
+            is_archived: false,
+            projects: [newProject],
+        });
     }
 }
 
@@ -186,26 +238,22 @@ function updateFilteredResults() {
         });
     }
 
+    const searchTerm = searchValue.value?.toLowerCase()?.trim() || '';
+    const groupIndexByKey = new Map<string, number>();
+
     for (const filterProject of props.projects) {
-        const projectNameIncludesSearchTerm = filterProject.name
-            .toLowerCase()
-            .includes(searchValue.value?.toLowerCase()?.trim() || '');
+        const projectNameIncludesSearchTerm = filterProject.name.toLowerCase().includes(searchTerm);
 
-        const clientNameIncludesSearchTerm = props.clients
-            .find((client) => client.id === filterProject.client_id)
-            ?.name.toLowerCase()
-            .includes(searchValue.value?.toLowerCase()?.trim() || '');
+        const clientName = filterProject.client_id
+            ? clientsById.value.get(filterProject.client_id)?.name
+            : undefined;
+        const clientNameIncludesSearchTerm = clientName?.toLowerCase().includes(searchTerm);
 
-        // check if one of the project tasks
-        const projectTasks = props.tasks.filter((task) => {
-            return task.project_id === filterProject.id;
-        });
+        const projectTasks = tasksByProject.value.get(filterProject.id) ?? [];
 
         const filteredTasks = projectTasks.filter((filterTask) => {
             return (
-                filterTask.name
-                    .toLowerCase()
-                    .includes(searchValue.value?.toLowerCase()?.trim() || '') &&
+                filterTask.name.toLowerCase().includes(searchTerm) &&
                 (!filterTask.is_done || filterTask.id === task.value)
             );
         });
@@ -215,10 +263,22 @@ function updateFilteredResults() {
             (!filterProject.is_archived || project.value === filterProject.id)
         ) {
             // search term matches project name
-            addProjectToFilterObject(tempFilteredClients, filterProject, filteredTasks, false);
+            addProjectToFilterObject(
+                tempFilteredClients,
+                groupIndexByKey,
+                filterProject,
+                filteredTasks,
+                false
+            );
         } else if (filteredTasks.length > 0 && !filterProject.is_archived) {
             // search term matches task name
-            addProjectToFilterObject(tempFilteredClients, filterProject, filteredTasks, true);
+            addProjectToFilterObject(
+                tempFilteredClients,
+                groupIndexByKey,
+                filterProject,
+                filteredTasks,
+                true
+            );
         }
     }
 
@@ -410,24 +470,18 @@ function moveHighlightDown() {
 const highlightedItemId = ref<string | null>(null);
 
 watch(highlightedItemId, () => {
-    const highlightedItem = dropdownViewport.value?.querySelector(
-        `[data-project-id="${highlightedItemId.value}"]`
+    if (highlightedItemId.value === null) {
+        return;
+    }
+    // The highlighted row may be virtualized out of the DOM, so scroll by index
+    // through the virtualizer instead of querying for the element.
+    const index = flatRows.value.findIndex(
+        (row) =>
+            (row.kind === 'project' && row.project.id === highlightedItemId.value) ||
+            (row.kind === 'task' && row.task.id === highlightedItemId.value)
     );
-    if (highlightedItem) {
-        highlightedItem.scrollIntoView({
-            block: 'nearest',
-            inline: 'nearest',
-        });
-    } else {
-        const highlightedTask = dropdownViewport.value?.querySelector(
-            `[data-task-id="${highlightedItemId.value}"]`
-        );
-        if (highlightedTask) {
-            highlightedTask.scrollIntoView({
-                block: 'nearest',
-                inline: 'nearest',
-            });
-        }
+    if (index !== -1) {
+        rowVirtualizer.value.scrollToIndex(index, { align: 'auto' });
     }
 });
 
@@ -558,62 +612,65 @@ const showCreateProject = ref(false);
                     @keydown.left.prevent="collapseProject" />
                 <div
                     ref="dropdownViewport"
-                    class="min-w-[350px] max-h-[350px] overflow-y-scroll relative"
+                    class="w-[400px] max-w-[calc(100vw-2rem)] max-h-[350px] overflow-y-scroll relative"
                     @mousemove="mouseEnterHighlightActivated = true">
-                    <template v-for="client in filteredResults" :key="client.id">
+                    <div :style="{ height: `${totalSize}px`, width: '100%', position: 'relative' }">
                         <div
-                            v-if="client.id !== 'no_project_no_client'"
-                            class="w-full pb-1 pt-2 px-2 text-text-tertiary text-xs font-semibold flex space-x-1 items-center">
-                            <span>
-                                {{ client.name }}
-                            </span>
-                        </div>
-                        <template
-                            v-for="projectWithTasks in client.projects"
-                            :key="projectWithTasks.id">
+                            v-for="{ virtualRow, row } in visibleRows"
+                            :key="row.key"
+                            :ref="measureRow"
+                            :data-index="virtualRow.index"
+                            class="absolute left-0 top-0 w-full"
+                            :style="{ transform: `translateY(${virtualRow.start}px)` }">
                             <div
+                                v-if="row.kind === 'client'"
+                                class="w-full pb-1 pt-2 px-2 text-text-tertiary text-xs font-semibold flex space-x-1 items-center">
+                                <span class="truncate">{{ row.name }}</span>
+                            </div>
+                            <div
+                                v-else-if="row.kind === 'project'"
                                 role="option"
                                 class="px-1 py-0.5 cursor-default"
-                                :value="projectWithTasks.id"
-                                :data-project-id="projectWithTasks.id"
-                                @click="selectProject(projectWithTasks.id)">
+                                :value="row.project.id"
+                                :data-project-id="row.project.id"
+                                @click="selectProject(row.project.id)">
                                 <div
                                     class="rounded-lg"
                                     :class="{
                                         'bg-card-background-active':
-                                            projectWithTasks.id === highlightedItemId,
+                                            row.project.id === highlightedItemId,
                                     }">
                                     <ProjectDropdownItem
                                         class="hover:!bg-transparent"
-                                        :selected="isProjectSelected(projectWithTasks)"
-                                        :name="projectWithTasks.name"
-                                        :color="projectWithTasks.color"
-                                        @mouseenter="setHighlightItemId(projectWithTasks.id)">
+                                        :selected="isProjectSelected(row.project)"
+                                        :name="row.project.name"
+                                        :color="row.project.color"
+                                        @mouseenter="setHighlightItemId(row.project.id)">
                                         <template #actions>
                                             <button
-                                                v-if="projectWithTasks.tasks.length > 0"
+                                                v-if="row.project.tasks.length > 0"
                                                 tabindex="-1"
-                                                class="px-2 py-0.5 mr-2 relative transition items-center rounded flex space-x-0.5 text-xs"
+                                                class="px-2 py-0.5 mr-2 relative transition items-center rounded flex space-x-0.5 text-xs shrink-0"
                                                 :class="{
                                                     'bg-white/5 text-text-secondary':
-                                                        projectWithTasks.expanded,
+                                                        row.project.expanded,
                                                     'hover:bg-white/5 hover:text-text-secondary text-text-tertiary':
-                                                        !projectWithTasks.expanded,
+                                                        !row.project.expanded,
                                                 }"
                                                 @click.prevent.stop="
                                                     () => {
-                                                        projectWithTasks.expanded =
-                                                            !projectWithTasks.expanded;
+                                                        row.project.expanded =
+                                                            !row.project.expanded;
                                                         searchInput?.focus();
                                                     }
                                                 ">
-                                                <span
-                                                    >{{ projectWithTasks.tasks.length }} Tasks</span
+                                                <span class="whitespace-nowrap"
+                                                    >{{ row.project.tasks.length }} Tasks</span
                                                 >
                                                 <ChevronDownIcon
                                                     :class="{
                                                         'transform rotate-180':
-                                                            projectWithTasks.expanded,
+                                                            row.project.expanded,
                                                     }"
                                                     class="w-4"></ChevronDownIcon>
                                             </button>
@@ -621,23 +678,23 @@ const showCreateProject = ref(false);
                                     </ProjectDropdownItem>
                                 </div>
                             </div>
-                            <div v-if="projectWithTasks.expanded" class="bg-quaternary">
-                                <div
-                                    v-for="task in projectWithTasks.tasks"
-                                    :key="task.id"
-                                    :data-task-id="task.id"
-                                    :class="{
-                                        'bg-card-background-active': task.id === highlightedItemId,
-                                    }"
-                                    class="flex items-center space-x-2 w-full px-5 py-1.5 text-start text-xs font-semibold leading-5 text-text-primary focus:outline-none focus:bg-card-background-active transition duration-150 ease-in-out"
-                                    @click="selectTask(task.id)"
-                                    @mouseenter="setHighlightItemId(task.id)">
-                                    <MinusIcon class="w-3 h-3 text-text-quaternary"></MinusIcon>
-                                    <span>{{ task.name }}</span>
-                                </div>
+                            <div
+                                v-else-if="row.kind === 'task'"
+                                :data-task-id="row.task.id"
+                                class="flex items-center space-x-2 w-full px-5 py-1.5 text-start text-xs font-semibold leading-5 text-text-primary focus:outline-none transition duration-150 ease-in-out"
+                                :class="
+                                    row.task.id === highlightedItemId
+                                        ? 'bg-card-background-active'
+                                        : 'bg-quaternary'
+                                "
+                                @click="selectTask(row.task.id)"
+                                @mouseenter="setHighlightItemId(row.task.id)">
+                                <MinusIcon
+                                    class="w-3 h-3 text-text-quaternary shrink-0"></MinusIcon>
+                                <span class="min-w-0 truncate">{{ row.task.name }}</span>
                             </div>
-                        </template>
-                    </template>
+                        </div>
+                    </div>
                 </div>
                 <div v-if="canCreateProject" class="hover:bg-card-background-active rounded-b-lg">
                     <button
diff --git a/resources/js/test-setup.ts b/resources/js/test-setup.ts
index ad1434b5..aefe512f 100644
--- a/resources/js/test-setup.ts
+++ b/resources/js/test-setup.ts
@@ -18,3 +18,13 @@ window.getTimezoneSetting = vi.fn(() => 'UTC');
 window.getWeekStartSetting = vi.fn(() => 'monday');
 window.getNumberFormat = vi.fn(() => 'point');
 window.getIntervalFormat = vi.fn(() => 'hours-minutes');
+
+// happy-dom has no layout engine, so every element reports offsetWidth/offsetHeight of 0.
+// TanStack Virtual (used by the project/task dropdown) measures via those properties, so
+// without a size it renders zero rows. Give elements a usable box so virtualized components
+// render their rows in component tests.
+Object.defineProperty(HTMLElement.prototype, 'offsetWidth', { configurable: true, get: () => 400 });
+Object.defineProperty(HTMLElement.prototype, 'offsetHeight', {
+    configurable: true,
+    get: () => 350,
+});