diff --git a/package.json b/package.json
index 5e3fea1f0..66ba375ec 100644
--- a/package.json
+++ b/package.json
@@ -26,15 +26,15 @@
     "@lerna/filter-options": "^4.0.0",
     "babel-loader": "^8.2.3",
     "better-docs": "^2.3.2",
-    "css-loader": "^6.5.1",
     "cross-env": "~7.0.3",
+    "css-loader": "^6.5.1",
     "file-loader": "^6.2.0",
     "jsdoc": "^3.6.7",
     "lerna": "^4.0.0",
     "prettier": "^2.5.0",
     "style-loader": "^3.3.1",
-    "typedoc": "^0.22.10",
-    "typescript": "^4.5.2",
+    "typedoc": "^0.23.15",
+    "typescript": "^4.8.3",
     "url-loader": "^4.1.1",
     "webpack": "^5.64.4",
     "webpack-cli": "^4.9.1",
diff --git a/packages/core/src/types.ts b/packages/core/src/types.ts
index 4e3a4dfa3..f5ff261ff 100644
--- a/packages/core/src/types.ts
+++ b/packages/core/src/types.ts
@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { DIRECTION } from './util/Constants';
+import { DIRECTION, IDENTITY_FIELD_NAME } from './util/Constants';
 import type Cell from './view/cell/Cell';
 import type CellState from './view/cell/CellState';
 import EventSource from './view/event/EventSource';
@@ -316,3 +316,13 @@ export interface PopupMenuItem extends HTMLElement {
   activeRow: PopupMenuItem | null;
   eventReceiver: HTMLElement | null;
 }
+
+export type IdentityObject = {
+  [IDENTITY_FIELD_NAME]?: string;
+  [k: string]: any;
+};
+
+export type IdentityFunction = {
+  (): any;
+  [IDENTITY_FIELD_NAME]?: string;
+};
diff --git a/packages/core/src/util/Constants.ts b/packages/core/src/util/Constants.ts
index 0b76dce7d..073e369ba 100644
--- a/packages/core/src/util/Constants.ts
+++ b/packages/core/src/util/Constants.ts
@@ -63,6 +63,12 @@ export const enum DIALECT {
     STRICTHTML = 'strictHtml',
 };
 
+/**
+ * Name of the field to be used to store the object ID. Default is
+ * <code>mxObjectId</code>.
+ */
+export const IDENTITY_FIELD_NAME = 'mxObjectId';
+
 /**
  * Defines the SVG namespace.
  */
diff --git a/packages/core/src/util/Dictionary.ts b/packages/core/src/util/Dictionary.ts
index bd13b0823..eb44313b1 100644
--- a/packages/core/src/util/Dictionary.ts
+++ b/packages/core/src/util/Dictionary.ts
@@ -16,6 +16,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { IdentityFunction, IdentityObject } from 'src/types';
 import ObjectIdentity from './ObjectIdentity';
 
 //type Dictionary<T, U> = {
@@ -34,7 +35,7 @@ type Visitor<MapKey, U> = (key: MapKey, value: U) => void;
  *
  * Constructs a new dictionary which allows object to be used as keys.
  */
-class Dictionary<T, U> {
+class Dictionary<T extends IdentityObject | IdentityFunction | null, U> {
   constructor() {
     this.clear();
   }
diff --git a/packages/core/src/util/ObjectIdentity.ts b/packages/core/src/util/ObjectIdentity.ts
index 27fdb86cb..b2439a02a 100644
--- a/packages/core/src/util/ObjectIdentity.ts
+++ b/packages/core/src/util/ObjectIdentity.ts
@@ -16,19 +16,10 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { IdentityFunction, IdentityObject } from 'src/types';
+import { IDENTITY_FIELD_NAME } from './Constants';
 import { getFunctionName } from './StringUtils';
 
-const FIELD_NAME = 'mxObjectId';
-
-type IdentityObject = {
-  [FIELD_NAME]?: string;
-  [k: string]: any;
-};
-
-type IdentityFunction = {
-  (): any;
-  [FIELD_NAME]?: string;
-};
 
 /**
  * @class
@@ -44,7 +35,7 @@ class ObjectIdentity {
    * Name of the field to be used to store the object ID. Default is
    * <code>mxObjectId</code>.
    */
-  static FIELD_NAME = FIELD_NAME;
+  static FIELD_NAME = IDENTITY_FIELD_NAME;
 
   /**
    * Current counter.
@@ -56,15 +47,15 @@ class ObjectIdentity {
    */
   static get(obj: IdentityObject | IdentityFunction | null) {
     if (obj) {
-      if (obj[FIELD_NAME] === null || obj[FIELD_NAME] === undefined) {
+      if (obj[IDENTITY_FIELD_NAME] === null || obj[IDENTITY_FIELD_NAME] === undefined) {
         if (typeof obj === 'object') {
           const ctor = getFunctionName(obj.constructor);
-          obj[FIELD_NAME] = `${ctor}#${ObjectIdentity.counter++}`;
+          obj[IDENTITY_FIELD_NAME] = `${ctor}#${ObjectIdentity.counter++}`;
         } else if (typeof obj === 'function') {
-          obj[FIELD_NAME] = `Function#${ObjectIdentity.counter++}`;
+          obj[IDENTITY_FIELD_NAME] = `Function#${ObjectIdentity.counter++}`;
         }
       }
-      return obj[FIELD_NAME] as string;
+      return obj[IDENTITY_FIELD_NAME] as string;
     }
     return null;
   }
@@ -73,7 +64,7 @@ class ObjectIdentity {
    * Deletes the ID from the given object or function.
    */
   static clear(obj: IdentityObject | IdentityFunction) {
-    delete obj[FIELD_NAME];
+    delete obj[IDENTITY_FIELD_NAME];
   }
 }
 
diff --git a/packages/core/src/view/cell/Cell.ts b/packages/core/src/view/cell/Cell.ts
index fa2e64f86..23689ded2 100644
--- a/packages/core/src/view/cell/Cell.ts
+++ b/packages/core/src/view/cell/Cell.ts
@@ -29,7 +29,7 @@ import { removeWhitespace } from '../../util/StringUtils';
 import { importNode } from '../../util/domUtils';
 import Codec from '../../serialization/Codec';
 
-import type { CellStyle, FilterFunction } from '../../types';
+import type { CellStyle, FilterFunction, IdentityObject } from '../../types';
 
 /**
  * Cells are the elements of the graph model. They represent the state
@@ -74,7 +74,7 @@ import type { CellStyle, FilterFunction } from '../../types';
  * ```
  * @class Cell
  */
-export class Cell {
+export class Cell implements IdentityObject {
   constructor(
     value: any = null,
     geometry: Geometry | null = null,
@@ -83,7 +83,6 @@ export class Cell {
     this.value = value;
     this.setGeometry(geometry);
     this.setStyle(style);
-
     if (this.onInit) {
       this.onInit();
     }
diff --git a/packages/core/src/view/cell/CellOverlay.ts b/packages/core/src/view/cell/CellOverlay.ts
index 57a309b82..f9eb3180c 100644
--- a/packages/core/src/view/cell/CellOverlay.ts
+++ b/packages/core/src/view/cell/CellOverlay.ts
@@ -21,6 +21,7 @@ import Rectangle from '../geometry/Rectangle';
 import EventSource from '../event/EventSource';
 import ImageBox from '../image/ImageBox';
 import CellState from './CellState';
+import ObjectIdentity from 'src/util/ObjectIdentity';
 
 /**
  * Extends {@link EventSource} to implement a graph overlay, represented by an icon
@@ -72,7 +73,7 @@ import CellState from './CellState';
  * values are <ALIGN_TOP>, <ALIGN_MIDDLE> and <ALIGN_BOTTOM>
  * (default).
  */
-class CellOverlay extends EventSource {
+class CellOverlay extends EventSource implements ObjectIdentity {
   constructor(
     image: ImageBox,
     tooltip: string | null = null,