diff --git a/.editorconfig b/.editorconfig
index 9775128ca33..5dc2447e503 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -433,7 +433,7 @@ ij_typescript_import_prefer_absolute_path = global
 ij_typescript_import_sort_members = true
 ij_typescript_import_sort_module_name = false
 ij_typescript_import_use_node_resolution = true
-ij_typescript_imports_wrap = on_every_item
+ij_typescript_imports_wrap = always
 ij_typescript_indent_case_from_switch = true
 ij_typescript_indent_chained_calls = true
 ij_typescript_indent_package_children = 0
diff --git a/config/locales/js-en.yml b/config/locales/js-en.yml
index 03b3c863c7d..e4c3a4158f1 100644
--- a/config/locales/js-en.yml
+++ b/config/locales/js-en.yml
@@ -582,6 +582,7 @@ en:
         watched: 'I am watching'
         all: 'All events'
         add: 'Add setting for project'
+        already_selected: 'This project is already selected'
         remove_projects: 'Remove notifications for projects'
         title: "Notification settings"
         self_notify: "I want to be notified of changes that I make myself"
diff --git a/frontend/src/app/features/user-preferences/notifications-settings/inline-create/notification-setting-inline-create.component.html b/frontend/src/app/features/user-preferences/notifications-settings/inline-create/notification-setting-inline-create.component.html
index 07d64e2269c..a3281d413ae 100644
--- a/frontend/src/app/features/user-preferences/notifications-settings/inline-create/notification-setting-inline-create.component.html
+++ b/frontend/src/app/features/user-preferences/notifications-settings/inline-create/notification-setting-inline-create.component.html
@@ -14,10 +14,26 @@
       [placeholder]="text.please_select"
       (change)="selectProject($event)"
       (keydown.escape)="active = false"
+      [fetchDataDirectly]="true"
       [filters]="autocompleterOptions.filters"
       [resource]="autocompleterOptions.resource"
       [getOptionsFn]="autocompleterOptions.getOptionsFn"
       appendTo="body"
   >
+    <ng-template op-autocompleter-option-tmp let-item let-index="index" let-search="search">
+      <div
+        *ngIf="item"
+        class="ng-option-label"
+      >
+        <!--Selectable option-->
+        <div [ngOptionHighlight]="search">{{ item.name }}</div>
+
+        <!-- Project already selected -->
+        <div
+          *ngIf="item.disabled"
+          class="ellipsis"
+        >{{ text.already_selected }}</div>
+      </div>
+    </ng-template>
   </op-autocompleter>
 </div>
\ No newline at end of file
diff --git a/frontend/src/app/features/user-preferences/notifications-settings/inline-create/notification-setting-inline-create.component.ts b/frontend/src/app/features/user-preferences/notifications-settings/inline-create/notification-setting-inline-create.component.ts
index 6baa16f6af8..60c699080eb 100644
--- a/frontend/src/app/features/user-preferences/notifications-settings/inline-create/notification-setting-inline-create.component.ts
+++ b/frontend/src/app/features/user-preferences/notifications-settings/inline-create/notification-setting-inline-create.component.ts
@@ -1,12 +1,20 @@
 import {
-  EventEmitter, Component, ChangeDetectionStrategy, Output, Input,
+  ChangeDetectionStrategy,
+  Component,
+  EventEmitter,
+  Input,
+  Output,
 } from '@angular/core';
 import { I18nService } from 'core-app/core/i18n/i18n.service';
-import { Observable, of } from 'rxjs';
-import { map } from 'rxjs/operators';
+import { Observable } from 'rxjs';
+import {
+  map,
+  withLatestFrom,
+} from 'rxjs/operators';
 import { APIV3Service } from 'core-app/core/apiv3/api-v3.service';
 import { ApiV3FilterBuilder } from 'core-app/shared/helpers/api-v3/api-v3-filter-builder';
 import { HalSourceLink } from 'core-app/features/hal/resources/hal-resource';
+import { UserPreferencesQuery } from 'core-app/features/user-preferences/state/user-preferences.query';
 
 export interface NotificationSettingProjectOption {
   name:string;
@@ -21,7 +29,7 @@ export interface NotificationSettingProjectOption {
 export class NotificationSettingInlineCreateComponent {
   @Input() userId:string;
 
-  @Output() onSelect = new EventEmitter<HalSourceLink>();
+  @Output() selected = new EventEmitter<HalSourceLink>();
 
   /** Active inline-create mode */
   active = false;
@@ -29,41 +37,47 @@ export class NotificationSettingInlineCreateComponent {
   text = {
     add_setting: this.I18n.t('js.notifications.settings.add'),
     please_select: this.I18n.t('js.placeholders.selection'),
+    already_selected: this.I18n.t('js.notifications.settings.already_selected'),
   };
 
   public autocompleterOptions = {
     filters: [],
     resource: 'default',
-    getOptionsFn: (query:string):Observable<any[]> => this.autocomplete(query),
+    getOptionsFn: (query:string):Observable<unknown[]> => this.autocomplete(query),
   };
 
   constructor(
     private I18n:I18nService,
     private apiV3Service:APIV3Service,
+    private query:UserPreferencesQuery,
   ) {
   }
 
-  selectProject($event:NotificationSettingProjectOption) {
-    this.onSelect.emit({ title: $event.name, href: $event.href });
+  selectProject($event:NotificationSettingProjectOption):void {
+    this.selected.emit({ title: $event.name, href: $event.href });
     this.active = false;
   }
 
-  private autocomplete(term:string):Observable<NotificationSettingProjectOption[]> {
-    if (!term) {
-      return of([]);
-    }
-
+  private autocomplete(term:string|null):Observable<NotificationSettingProjectOption[]> {
     const filters = new ApiV3FilterBuilder()
-      .add('name_and_identifier', '~', [term])
       .add('visible', '=', [this.userId]);
 
+    if (term) {
+      filters.add('name_and_identifier', '~', [term]);
+    }
+
     return this
       .apiV3Service
       .projects
       .filtered(filters)
       .get()
       .pipe(
-        map((collection) => collection.elements.map((project) => ({ href: project.href!, name: project.name }))),
+        withLatestFrom(this.query.selectedProjects$),
+        map(([collection, selected]) => collection.elements.map(
+          (project) => (
+            { href: project.href || '', name: project.name, disabled: selected.has(project.href) }
+          ),
+        )),
       );
   }
 }
diff --git a/frontend/src/app/features/user-preferences/notifications-settings/table/notification-settings-table.component.html b/frontend/src/app/features/user-preferences/notifications-settings/table/notification-settings-table.component.html
index be01ba4a9f0..bfb7ebdf6bd 100644
--- a/frontend/src/app/features/user-preferences/notifications-settings/table/notification-settings-table.component.html
+++ b/frontend/src/app/features/user-preferences/notifications-settings/table/notification-settings-table.component.html
@@ -77,7 +77,7 @@
     <op-notification-setting-inline-create
         *ngIf="userId"
         [userId]="userId"
-        (onSelect)="addRow($event)"
+        (selected)="addRow($event)"
         data-qa-selector="notification-setting-inline-create"
     ></op-notification-setting-inline-create>
   </div>
diff --git a/frontend/src/app/features/user-preferences/state/user-preferences.query.ts b/frontend/src/app/features/user-preferences/state/user-preferences.query.ts
index 6c04e8f96bc..7cf0f1d62b7 100644
--- a/frontend/src/app/features/user-preferences/state/user-preferences.query.ts
+++ b/frontend/src/app/features/user-preferences/state/user-preferences.query.ts
@@ -25,6 +25,15 @@ export class UserPreferencesQuery extends Query<UserPreferencesModel> {
       map((settings) => settings.filter((notification) => notification._links.project.href !== null)),
     );
 
+  /** Selected projects */
+  selectedProjects$ = this
+    .notificationSettings$
+    .pipe(
+      map((notifications) => (
+        new Set(notifications.map((setting) => setting._links.project?.href))
+      )),
+    );
+
   preferences$ = this.select();
 
   constructor(protected store:UserPreferencesStore) {
diff --git a/spec/features/users/notifications/shared_examples.rb b/spec/features/users/notifications/shared_examples.rb
index cda75f31896..43cfc13fa88 100644
--- a/spec/features/users/notifications/shared_examples.rb
+++ b/spec/features/users/notifications/shared_examples.rb
@@ -59,6 +59,13 @@ shared_examples 'notification settings workflow' do
       expect(in_app.mentioned).to be_truthy
       expect(in_app.watched).to be_falsey
       expect(in_app.all).to be_truthy
+
+      # Trying to add the same project again will not be possible (Regression #38072)
+      click_button 'Add setting for project'
+      container = page.find('[data-qa-selector="notification-setting-inline-create"] ng-select')
+      settings_page.search_autocomplete container, query: project.name, results_selector: 'body'
+      expect(page).to have_text 'This project is already selected'
+      expect(page).to have_selector('.ng-option-disabled', text: project.name)
     end
   end
 end