diff --git a/models/attachment/src/index.ts b/models/attachment/src/index.ts
index a81b312ed0..274cc3dffa 100644
--- a/models/attachment/src/index.ts
+++ b/models/attachment/src/index.ts
@@ -64,11 +64,11 @@ export function createModel (builder: Builder): void {
     presenter: attachment.component.AttachmentPresenter
   })
 
-  builder.mixin(attachment.class.Attachment, core.class.Class, view.mixin.AttributeEditor, {
+  builder.mixin(attachment.class.Attachment, core.class.Class, view.mixin.CollectionEditor, {
     editor: attachment.component.Attachments
   })
 
-  builder.mixin(attachment.class.Photo, core.class.Class, view.mixin.AttributeEditor, {
+  builder.mixin(attachment.class.Photo, core.class.Class, view.mixin.CollectionEditor, {
     editor: attachment.component.Photos
   })
 
diff --git a/models/contact/src/index.ts b/models/contact/src/index.ts
index 12d1e7f8e7..d9f1c464b4 100644
--- a/models/contact/src/index.ts
+++ b/models/contact/src/index.ts
@@ -181,6 +181,14 @@ export function createModel (builder: Builder): void {
     editor: contact.component.OrganizationEditor
   })
 
+  builder.mixin(contact.class.Person, core.class.Class, view.mixin.AttributeEditor, {
+    editor: contact.component.PersonEditor
+  })
+
+  builder.mixin(contact.class.Employee, core.class.Class, view.mixin.AttributeEditor, {
+    editor: contact.component.PersonEditor
+  })
+
   builder.mixin(contact.class.Channel, core.class.Class, view.mixin.AttributePresenter, {
     presenter: contact.component.ChannelsPresenter
   })
diff --git a/models/contact/src/plugin.ts b/models/contact/src/plugin.ts
index 90b5a09b97..bb175b2de9 100644
--- a/models/contact/src/plugin.ts
+++ b/models/contact/src/plugin.ts
@@ -35,6 +35,7 @@ export default mergeIds(contactId, contact, {
     OrganizationPresenter: '' as AnyComponent,
     Contacts: '' as AnyComponent,
     EmployeeAccountPresenter: '' as AnyComponent,
+    PersonEditor: '' as AnyComponent,
     OrganizationEditor: '' as AnyComponent
   },
   string: {
@@ -47,7 +48,6 @@ export default mergeIds(contactId, contact, {
     Location: '' as IntlString,
     Channel: '' as IntlString,
     ChannelProvider: '' as IntlString,
-    Person: '' as IntlString,
     Employee: '' as IntlString,
     Value: '' as IntlString,
     Phone: '' as IntlString,
diff --git a/models/inventory/src/index.ts b/models/inventory/src/index.ts
index ce45442896..899927b8d0 100644
--- a/models/inventory/src/index.ts
+++ b/models/inventory/src/index.ts
@@ -86,7 +86,7 @@ export function createModel (builder: Builder): void {
     presenter: inventory.component.VariantPresenter
   })
 
-  builder.mixin(inventory.class.Variant, core.class.Class, view.mixin.AttributeEditor, {
+  builder.mixin(inventory.class.Variant, core.class.Class, view.mixin.CollectionEditor, {
     editor: inventory.component.Variants
   })
 
diff --git a/models/lead/src/index.ts b/models/lead/src/index.ts
index 514fc41ba0..c1a87d4161 100644
--- a/models/lead/src/index.ts
+++ b/models/lead/src/index.ts
@@ -185,7 +185,7 @@ export function createModel (builder: Builder): void {
     presenter: lead.component.LeadPresenter
   })
 
-  builder.mixin(lead.class.Lead, core.class.Class, view.mixin.AttributeEditor, {
+  builder.mixin(lead.class.Lead, core.class.Class, view.mixin.CollectionEditor, {
     editor: lead.component.Leads
   })
 
diff --git a/models/recruit/src/index.ts b/models/recruit/src/index.ts
index 02316989e0..fd0319af94 100644
--- a/models/recruit/src/index.ts
+++ b/models/recruit/src/index.ts
@@ -133,7 +133,7 @@ export function createModel (builder: Builder): void {
     }
   })
 
-  builder.mixin(recruit.class.Applicant, core.class.Class, view.mixin.AttributeEditor, {
+  builder.mixin(recruit.class.Applicant, core.class.Class, view.mixin.CollectionEditor, {
     editor: recruit.component.Applications
   })
 
diff --git a/models/recruit/src/review.ts b/models/recruit/src/review.ts
index 06fea95bb0..c56ac6f4c2 100644
--- a/models/recruit/src/review.ts
+++ b/models/recruit/src/review.ts
@@ -43,7 +43,7 @@ export function createReviewModel (builder: Builder): void {
     }
   })
 
-  builder.mixin(recruit.class.Review, core.class.Class, view.mixin.AttributeEditor, {
+  builder.mixin(recruit.class.Review, core.class.Class, view.mixin.CollectionEditor, {
     editor: recruit.component.Reviews
   })
 
@@ -135,7 +135,7 @@ function createTableViewlet (builder: Builder): void {
     config: reviewTableConfig
   })
 
-  builder.mixin(recruit.class.Opinion, core.class.Class, view.mixin.AttributeEditor, {
+  builder.mixin(recruit.class.Opinion, core.class.Class, view.mixin.CollectionEditor, {
     editor: recruit.component.Opinions
   })
 }
diff --git a/models/tags/src/index.ts b/models/tags/src/index.ts
index e1a5d6ae1f..5e5c8d0d76 100644
--- a/models/tags/src/index.ts
+++ b/models/tags/src/index.ts
@@ -84,7 +84,7 @@ export class TTagCategory extends TDoc implements TagCategory {
 export function createModel (builder: Builder): void {
   builder.createModel(TTagElement, TTagReference, TTagCategory)
 
-  builder.mixin(tags.class.TagReference, core.class.Class, view.mixin.AttributeEditor, {
+  builder.mixin(tags.class.TagReference, core.class.Class, view.mixin.CollectionEditor, {
     editor: tags.component.Tags
   })
 
diff --git a/models/task/src/index.ts b/models/task/src/index.ts
index 35bbdd9c3f..06e415e555 100644
--- a/models/task/src/index.ts
+++ b/models/task/src/index.ts
@@ -39,7 +39,8 @@ import presentation from '@anticrm/model-presentation'
 import view, { actionTemplates as viewTemplates, createAction, template } from '@anticrm/model-view'
 import { IntlString } from '@anticrm/platform'
 import { ViewAction } from '@anticrm/view'
-import type {
+import {
+  DOMAIN_STATE,
   DoneState,
   DoneStateTemplate,
   Issue,
@@ -65,7 +66,6 @@ export { createKanbanTemplate, createSequence, taskOperation } from './migration
 export { default } from './plugin'
 
 export const DOMAIN_TASK = 'task' as Domain
-export const DOMAIN_STATE = 'state' as Domain
 export const DOMAIN_KANBAN = 'kanban' as Domain
 @Model(task.class.State, core.class.Doc, DOMAIN_STATE, [task.interface.DocWithRank])
 @UX(task.string.TaskState, task.icon.TaskState, undefined, 'rank')
@@ -454,7 +454,7 @@ export function createModel (builder: Builder): void {
     task.viewlet.Kanban
   )
 
-  builder.mixin(task.class.TodoItem, core.class.Class, view.mixin.AttributeEditor, {
+  builder.mixin(task.class.TodoItem, core.class.Class, view.mixin.CollectionEditor, {
     editor: task.component.Todos
   })
 
diff --git a/models/view/src/index.ts b/models/view/src/index.ts
index dac42cbabe..c0620be313 100644
--- a/models/view/src/index.ts
+++ b/models/view/src/index.ts
@@ -24,6 +24,7 @@ import type {
   ActionCategory,
   AttributeEditor,
   AttributePresenter,
+  CollectionEditor,
   HTMLPresenter,
   IgnoreActions,
   KeyBinding,
@@ -77,6 +78,11 @@ export class TAttributeEditor extends TClass implements AttributeEditor {
   editor!: AnyComponent
 }
 
+@Mixin(view.mixin.CollectionEditor, core.class.Class)
+export class TCollectionEditor extends TClass implements CollectionEditor {
+  editor!: AnyComponent
+}
+
 @Mixin(view.mixin.AttributePresenter, core.class.Class)
 export class TAttributePresenter extends TClass implements AttributePresenter {
   presenter!: AnyComponent
@@ -210,6 +216,7 @@ export function createModel (builder: Builder): void {
   builder.createModel(
     TAttributeEditor,
     TAttributePresenter,
+    TCollectionEditor,
     TObjectEditor,
     TViewletDescriptor,
     TViewlet,
@@ -252,6 +259,10 @@ export function createModel (builder: Builder): void {
     editor: view.component.NumberTypeEditor
   })
 
+  builder.mixin(core.class.RefTo, core.class.Class, view.mixin.ObjectEditor, {
+    editor: view.component.RefEditor
+  })
+
   builder.createDoc(
     view.class.ActionCategory,
     core.space.Model,
diff --git a/models/view/src/plugin.ts b/models/view/src/plugin.ts
index 340adcb963..36f5b859bb 100644
--- a/models/view/src/plugin.ts
+++ b/models/view/src/plugin.ts
@@ -77,7 +77,8 @@ export default mergeIds(viewId, view, {
     StringTypeEditor: '' as AnyComponent,
     BooleanTypeEditor: '' as AnyComponent,
     NumberTypeEditor: '' as AnyComponent,
-    DateTypeEditor: '' as AnyComponent
+    DateTypeEditor: '' as AnyComponent,
+    RefEditor: '' as AnyComponent
   },
   string: {
     Table: '' as IntlString,
diff --git a/plugins/contact-resources/src/components/PersonEditor.svelte b/plugins/contact-resources/src/components/PersonEditor.svelte
new file mode 100644
index 0000000000..ba5ef76aa9
--- /dev/null
+++ b/plugins/contact-resources/src/components/PersonEditor.svelte
@@ -0,0 +1,30 @@
+<!--
+// Copyright © 2022 Hardcore Engineering Inc.
+//
+// Licensed under the Eclipse Public License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License. You may
+// obtain a copy of the License at https://www.eclipse.org/legal/epl-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//
+// See the License for the specific language governing permissions and
+// limitations under the License.
+-->
+<script lang="ts">
+  import { Person } from '@anticrm/contact'
+  import { Ref, RefTo } from '@anticrm/core'
+  import { IntlString } from '@anticrm/platform'
+  import { UserBox } from '@anticrm/presentation'
+  import contact from '../plugin'
+
+  export let value: Ref<Person> | undefined
+  export let label: IntlString = contact.string.Person
+  export let onChange: (value: any) => void
+  export let type: RefTo<Person> | undefined
+
+  $: _class = type?.to ?? contact.class.Person
+</script>
+
+<UserBox {_class} {label} kind={'link'} size={'large'} bind:value on:change={onChange} />
diff --git a/plugins/contact-resources/src/index.ts b/plugins/contact-resources/src/index.ts
index dc4f101c93..f942d786e9 100644
--- a/plugins/contact-resources/src/index.ts
+++ b/plugins/contact-resources/src/index.ts
@@ -37,6 +37,7 @@ import SocialEditor from './components/SocialEditor.svelte'
 import contact from './plugin'
 import EmployeeAccountPresenter from './components/EmployeeAccountPresenter.svelte'
 import OrganizationEditor from './components/OrganizationEditor.svelte'
+import PersonEditor from './components/PersonEditor.svelte'
 import OrganizationSelector from './components/OrganizationSelector.svelte'
 
 export { Channels, ChannelsEditor, ContactPresenter, ChannelsView, OrganizationSelector, ChannelsDropdown }
@@ -58,6 +59,7 @@ async function queryContact (
 
 export default async (): Promise<Resources> => ({
   component: {
+    PersonEditor,
     OrganizationEditor,
     ContactPresenter,
     PersonPresenter,
diff --git a/plugins/contact-resources/src/plugin.ts b/plugins/contact-resources/src/plugin.ts
index 39e2611e76..520c102229 100644
--- a/plugins/contact-resources/src/plugin.ts
+++ b/plugins/contact-resources/src/plugin.ts
@@ -33,6 +33,7 @@ export default mergeIds(contactId, contact, {
     CreateOrganizations: '' as IntlString,
     Organizations: '' as IntlString,
     Organization: '' as IntlString,
+    Person: '' as IntlString,
     SelectFolder: '' as IntlString,
     OrganizationsFolder: '' as IntlString,
     PersonsFolder: '' as IntlString,
diff --git a/plugins/task-resources/src/components/TaskHeader.svelte b/plugins/task-resources/src/components/TaskHeader.svelte
index 31fb9982f1..879e2097ed 100644
--- a/plugins/task-resources/src/components/TaskHeader.svelte
+++ b/plugins/task-resources/src/components/TaskHeader.svelte
@@ -17,7 +17,6 @@
   import contact from '@anticrm/contact'
   import core, { Class, Doc, Mixin, Ref, RefTo } from '@anticrm/core'
   import { AttributesBar, getClient, KeyedAttribute, UserBox } from '@anticrm/presentation'
-  import { Label } from '@anticrm/ui'
   import { Task } from '@anticrm/task'
   import task from '../plugin'
   import { DocAttributeBar } from '@anticrm/view-resources'
@@ -78,38 +77,10 @@
     <AttributesBar {object} keys={['doneState', 'state']} showHeader={false} />
   </div>
 {:else}
-  <div class="task-attr-prop mb-4">
-    <span class="fs-bold"><Label label={task.string.TaskAssignee} /></span>
-    <UserBox
-      _class={getAssigneeClass(object)}
-      label={assigneeTitle}
-      placeholder={assigneeTitle}
-      kind={'link'}
-      size={'large'}
-      bind:value={object.assignee}
-      on:change={change}
-      allowDeselect
-      titleDeselect={task.string.TaskUnAssign}
-    />
-    <div style:grid-column={'1/3'}>
-      <AttributesBar {object} keys={['doneState', 'state']} vertical />
-    </div>
-  </div>
-  <DocAttributeBar {object} ignoreKeys={[...ignoreKeys, ...taskKeys]} {mixins} on:update />
+  <DocAttributeBar {object} {ignoreKeys} {mixins} on:update />
 {/if}
 
 <style lang="scss">
-  .task-attr-prop {
-    display: grid;
-    grid-template-columns: 1fr 1.5fr;
-    grid-template-rows: minmax(2rem, auto);
-    grid-auto-flow: row;
-    justify-content: start;
-    align-items: center;
-    gap: 1rem;
-    width: 100%;
-    height: min-content;
-  }
   .task-attr-header {
     display: flex;
     justify-content: space-between;
diff --git a/plugins/task-resources/src/components/state/StateEditor.svelte b/plugins/task-resources/src/components/state/StateEditor.svelte
index e841b462f6..35575abc34 100644
--- a/plugins/task-resources/src/components/state/StateEditor.svelte
+++ b/plugins/task-resources/src/components/state/StateEditor.svelte
@@ -14,7 +14,7 @@
 // limitations under the License.
 -->
 <script lang="ts">
-  import { Ref } from '@anticrm/core'
+  import { Ref, Space } from '@anticrm/core'
   import task, { State } from '@anticrm/task'
   import { createQuery } from '@anticrm/presentation'
   import type { ButtonKind, ButtonSize } from '@anticrm/ui'
@@ -23,6 +23,7 @@
   import StatesPopup from './StatesPopup.svelte'
 
   export let value: Ref<State>
+  export let space: Ref<Space>
   export let onChange: (value: any) => void
   export let kind: ButtonKind = 'no-border'
   export let size: ButtonSize = 'small'
@@ -41,26 +42,26 @@
   )
 </script>
 
-{#if state}
-  <Button
-    width="min-content"
-    {kind}
-    {size}
-    on:click={(ev) => {
-      if (!opened) {
-        opened = true
-        showPopup(StatesPopup, { space: state.space }, eventToHTMLElement(ev), (result) => {
-          if (result && result._id !== value) {
-            value = result._id
-            onChange(value)
-          }
-          opened = false
-        })
-      }
-    }}
-  >
-    <svelte:fragment slot="content">
+<Button
+  width="min-content"
+  {kind}
+  {size}
+  on:click={(ev) => {
+    if (!opened) {
+      opened = true
+      showPopup(StatesPopup, { space }, eventToHTMLElement(ev), (result) => {
+        if (result && result._id !== value) {
+          value = result._id
+          onChange(value)
+        }
+        opened = false
+      })
+    }
+  }}
+>
+  <svelte:fragment slot="content">
+    {#if state}
       <StatePresenter value={state} />
-    </svelte:fragment>
-  </Button>
-{/if}
+    {/if}
+  </svelte:fragment>
+</Button>
diff --git a/plugins/task-resources/src/components/state/StatePresenter.svelte b/plugins/task-resources/src/components/state/StatePresenter.svelte
index c400ea0ff6..030b1e8a82 100644
--- a/plugins/task-resources/src/components/state/StatePresenter.svelte
+++ b/plugins/task-resources/src/components/state/StatePresenter.svelte
@@ -23,7 +23,7 @@
 {#if value}
   <div class="flex-row-center">
     <div class="state-container" style="background-color: {getPlatformColor(value.color)}" />
-    <span class="overflow-label">{value.title ?? ''}</span>
+    <span class="overflow-label">{value.title}</span>
   </div>
 {/if}
 
diff --git a/plugins/task/src/index.ts b/plugins/task/src/index.ts
index 8c60b21032..451a3f1718 100644
--- a/plugins/task/src/index.ts
+++ b/plugins/task/src/index.ts
@@ -14,13 +14,30 @@
 //
 
 import type { Employee } from '@anticrm/contact'
-import { AttachedDoc, Class, Doc, Interface, Markup, Mixin, Ref, Space, Timestamp, TxOperations } from '@anticrm/core'
+import {
+  AttachedDoc,
+  Class,
+  Doc,
+  Domain,
+  Interface,
+  Markup,
+  Mixin,
+  Ref,
+  Space,
+  Timestamp,
+  TxOperations
+} from '@anticrm/core'
 import type { Asset, IntlString, Plugin } from '@anticrm/platform'
 import { plugin } from '@anticrm/platform'
 import type { AnyComponent } from '@anticrm/ui'
 import { ViewletDescriptor } from '@anticrm/view'
 import { genRanks } from './utils'
 
+/**
+ * @public
+ */
+export const DOMAIN_STATE = 'state' as Domain
+
 /**
  * @public
  */
diff --git a/plugins/view-resources/src/components/CreateAttribute.svelte b/plugins/view-resources/src/components/CreateAttribute.svelte
index 2ca408702d..3e2d654683 100644
--- a/plugins/view-resources/src/components/CreateAttribute.svelte
+++ b/plugins/view-resources/src/components/CreateAttribute.svelte
@@ -13,7 +13,7 @@
 // limitations under the License.
 -->
 <script lang="ts">
-  import core, { AnyAttribute, Class, Data, generateId, IndexKind, PropertyType, Ref, Space, Type } from '@anticrm/core'
+  import core, { AnyAttribute, Class, Data, Doc, generateId, IndexKind, PropertyType, Ref, Type } from '@anticrm/core'
   import { getEmbeddedLabel } from '@anticrm/platform'
   import { Card, getClient } from '@anticrm/presentation'
   import { AnyComponent, Component, DropdownLabelsIntl, EditBox, Label } from '@anticrm/ui'
@@ -21,7 +21,7 @@
   import { createEventDispatcher } from 'svelte'
   import view from '../plugin'
 
-  export let _class: Ref<Class<Space>>
+  export let _class: Ref<Class<Doc>>
   let name: string
   let type: Type<PropertyType> | undefined
   let index: IndexKind | undefined
diff --git a/plugins/view-resources/src/components/EditDoc.svelte b/plugins/view-resources/src/components/EditDoc.svelte
index f86c54dddb..73dad3e3bd 100644
--- a/plugins/view-resources/src/components/EditDoc.svelte
+++ b/plugins/view-resources/src/components/EditDoc.svelte
@@ -135,8 +135,8 @@
 
   async function getCollectionEditor (key: KeyedAttribute): Promise<AnyComponent> {
     const attrClass = getAttributePresenterClass(key.attr)
-    const clazz = client.getHierarchy().getClass(attrClass)
-    const editorMixin = client.getHierarchy().as(clazz, view.mixin.AttributeEditor)
+    const clazz = hierarchy.getClass(attrClass)
+    const editorMixin = hierarchy.as(clazz, view.mixin.CollectionEditor)
     return editorMixin.editor
   }
 
diff --git a/plugins/view-resources/src/components/typeEditors/RefEditor.svelte b/plugins/view-resources/src/components/typeEditors/RefEditor.svelte
new file mode 100644
index 0000000000..1ed26c1ccf
--- /dev/null
+++ b/plugins/view-resources/src/components/typeEditors/RefEditor.svelte
@@ -0,0 +1,52 @@
+<!--
+// Copyright © 2022 Hardcore Engineering Inc.
+//
+// Licensed under the Eclipse Public License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License. You may
+// obtain a copy of the License at https://www.eclipse.org/legal/epl-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//
+// See the License for the specific language governing permissions and
+// limitations under the License.
+-->
+<script lang="ts">
+  import core, { Class, Doc, Ref } from '@anticrm/core'
+  import { TypeRef } from '@anticrm/model'
+  import { getClient } from '@anticrm/presentation'
+  import { DOMAIN_STATE } from '@anticrm/task'
+  import { DropdownLabelsIntl, Label } from '@anticrm/ui'
+  import view from '../../plugin'
+  import { createEventDispatcher } from 'svelte'
+
+  const dispatch = createEventDispatcher()
+  const client = getClient()
+  const hierarchy = client.getHierarchy()
+
+  const descendants = hierarchy.getDescendants(core.class.Doc)
+  const classes = descendants
+    .map((p) => hierarchy.getClass(p))
+    .filter((p) => {
+      return (
+        hierarchy.hasMixin(p, view.mixin.AttributeEditor) &&
+        p.label !== undefined &&
+        hierarchy.getDomain(p._id) !== DOMAIN_STATE
+      )
+    })
+    .map((p) => {
+      return { id: p._id, label: p.label }
+    })
+
+  let refClass: Ref<Class<Doc>>
+
+  $: dispatch('change', { type: TypeRef(refClass) })
+</script>
+
+<div class="flex-row-center flex-grow">
+  <Label label={core.string.Class} />
+  <div class="ml-4">
+    <DropdownLabelsIntl label={core.string.Class} items={classes} width="8rem" bind:selected={refClass} />
+  </div>
+</div>
diff --git a/plugins/view-resources/src/index.ts b/plugins/view-resources/src/index.ts
index 4b0a370394..c2a5bee4bd 100644
--- a/plugins/view-resources/src/index.ts
+++ b/plugins/view-resources/src/index.ts
@@ -43,6 +43,7 @@ import StringTypeEditor from './components/typeEditors/StringTypeEditor.svelte'
 import BooleanTypeEditor from './components/typeEditors/BooleanTypeEditor.svelte'
 import DateTypeEditor from './components/typeEditors/DateTypeEditor.svelte'
 import NumberTypeEditor from './components/typeEditors/NumberTypeEditor.svelte'
+import RefEditor from './components/typeEditors/RefEditor.svelte'
 import DocAttributeBar from './components/DocAttributeBar.svelte'
 
 export { getActions } from './actions'
@@ -63,6 +64,7 @@ export default async (): Promise<Resources> => ({
     StringTypeEditor,
     BooleanTypeEditor,
     NumberTypeEditor,
+    RefEditor,
     DateTypeEditor,
     SpacePresenter,
     StringEditor,
diff --git a/plugins/view/src/index.ts b/plugins/view/src/index.ts
index f9e1f5e583..cea702ac6e 100644
--- a/plugins/view/src/index.ts
+++ b/plugins/view/src/index.ts
@@ -39,6 +39,13 @@ export interface AttributeEditor extends Class<Doc> {
   editor: AnyComponent
 }
 
+/**
+ * @public
+ */
+export interface CollectionEditor extends Class<Doc> {
+  editor: AnyComponent
+}
+
 /**
  * @public
  */
@@ -286,6 +293,7 @@ export interface ObjectFactory extends Class<Obj> {
 const view = plugin(viewId, {
   mixin: {
     AttributeEditor: '' as Ref<Mixin<AttributeEditor>>,
+    CollectionEditor: '' as Ref<Mixin<CollectionEditor>>,
     AttributePresenter: '' as Ref<Mixin<AttributePresenter>>,
     ObjectEditor: '' as Ref<Mixin<ObjectEditor>>,
     ObjectEditorHeader: '' as Ref<Mixin<ObjectEditorHeader>>,