diff --git a/packages/notebook/src/browser/service/notebook-cell-editor-service.ts b/packages/notebook/src/browser/service/notebook-cell-editor-service.ts
index e1d338a4b7602..53268eb62b4ec 100644
--- a/packages/notebook/src/browser/service/notebook-cell-editor-service.ts
+++ b/packages/notebook/src/browser/service/notebook-cell-editor-service.ts
@@ -15,12 +15,17 @@
 // *****************************************************************************
 
 import { Emitter, URI } from '@theia/core';
-import { injectable } from '@theia/core/shared/inversify';
+import { inject, injectable, postConstruct } from '@theia/core/shared/inversify';
 import { SimpleMonacoEditor } from '@theia/monaco/lib/browser/simple-monaco-editor';
+import { NotebookEditorWidgetService } from './notebook-editor-widget-service';
+import { CellUri } from '../../common';
 
 @injectable()
 export class NotebookCellEditorService {
 
+    @inject(NotebookEditorWidgetService)
+    protected readonly notebookEditorWidgetService: NotebookEditorWidgetService;
+
     protected onDidChangeCellEditorsEmitter = new Emitter<void>();
     readonly onDidChangeCellEditors = this.onDidChangeCellEditorsEmitter.event;
 
@@ -31,6 +36,17 @@ export class NotebookCellEditorService {
 
     protected currentCellEditors: Map<string, SimpleMonacoEditor> = new Map();
 
+    @postConstruct()
+    protected init(): void {
+        this.notebookEditorWidgetService.onDidChangeCurrentEditor(editor => {
+            // if defocus notebook editor or another notebook editor is focused, clear the active cell
+            if (!editor || (this.currentActiveCell && CellUri.parse(this.currentActiveCell.uri)?.notebook.toString() !== editor?.model?.uri.toString())) {
+                this.currentActiveCell = undefined;
+                this.onDidChangeFocusedCellEditorEmitter.fire(undefined);
+            }
+        });
+    }
+
     get allCellEditors(): SimpleMonacoEditor[] {
         return Array.from(this.currentCellEditors.values());
     }
@@ -46,8 +62,10 @@ export class NotebookCellEditorService {
     }
 
     editorFocusChanged(editor?: SimpleMonacoEditor): void {
-        this.currentActiveCell = editor;
-        this.onDidChangeFocusedCellEditorEmitter.fire(editor);
+        if (editor) {
+            this.currentActiveCell = editor;
+            this.onDidChangeFocusedCellEditorEmitter.fire(editor);
+        }
     }
 
     getActiveCell(): SimpleMonacoEditor | undefined {
diff --git a/packages/notebook/src/browser/service/notebook-editor-widget-service.ts b/packages/notebook/src/browser/service/notebook-editor-widget-service.ts
index b585834ce6013..c54faa00db166 100644
--- a/packages/notebook/src/browser/service/notebook-editor-widget-service.ts
+++ b/packages/notebook/src/browser/service/notebook-editor-widget-service.ts
@@ -45,13 +45,23 @@ export class NotebookEditorWidgetService {
     protected readonly onDidChangeFocusedEditorEmitter = new Emitter<NotebookEditorWidget | undefined>();
     readonly onDidChangeFocusedEditor = this.onDidChangeFocusedEditorEmitter.event;
 
+    protected readonly onDidChangeCurrentEditorEmitter = new Emitter<NotebookEditorWidget | undefined>();
+    readonly onDidChangeCurrentEditor = this.onDidChangeCurrentEditorEmitter.event;
+
     focusedEditor?: NotebookEditorWidget = undefined;
 
+    currentEditor?: NotebookEditorWidget = undefined;
+
     @postConstruct()
     protected init(): void {
         this.applicationShell.onDidChangeActiveWidget(event => {
             this.notebookEditorFocusChanged(event.newValue as NotebookEditorWidget, event.newValue instanceof NotebookEditorWidget);
         });
+        this.applicationShell.onDidChangeCurrentWidget(event => {
+            if (event.newValue instanceof NotebookEditorWidget || event.oldValue instanceof NotebookEditorWidget) {
+                this.currentNotebookEditorChanged(event.newValue);
+            }
+        });
     }
 
     // --- editor management
@@ -98,4 +108,14 @@ export class NotebookEditorWidgetService {
         }
     }
 
+    currentNotebookEditorChanged(newEditor: unknown): void {
+        if (newEditor instanceof NotebookEditorWidget) {
+            this.currentEditor = newEditor;
+            this.onDidChangeCurrentEditorEmitter.fire(newEditor);
+        } else if (this.currentEditor?.isDisposed || !this.currentEditor?.isVisible) {
+            this.currentEditor = undefined;
+            this.onDidChangeCurrentEditorEmitter.fire(undefined);
+        }
+    }
+
 }
diff --git a/packages/plugin-ext/src/main/browser/editors-and-documents-main.ts b/packages/plugin-ext/src/main/browser/editors-and-documents-main.ts
index f88d72dc27b0b..18af7ae744aed 100644
--- a/packages/plugin-ext/src/main/browser/editors-and-documents-main.ts
+++ b/packages/plugin-ext/src/main/browser/editors-and-documents-main.ts
@@ -250,7 +250,7 @@ class EditorAndDocumentStateComputer implements Disposable {
 
         this.toDispose.push(this.cellEditorService.onDidChangeCellEditors(() => this.update()));
 
-        this.toDispose.push(this.notebookWidgetService.onDidChangeFocusedEditor(() => {
+        this.toDispose.push(this.notebookWidgetService.onDidChangeCurrentEditor(() => {
             this.currentState = this.currentState && new EditorAndDocumentState(
                 this.currentState.documents,
                 this.currentState.editors,
diff --git a/packages/plugin-ext/src/main/browser/notebooks/notebook-documents-and-editors-main.ts b/packages/plugin-ext/src/main/browser/notebooks/notebook-documents-and-editors-main.ts
index 11285a9f55101..87efcbb53de12 100644
--- a/packages/plugin-ext/src/main/browser/notebooks/notebook-documents-and-editors-main.ts
+++ b/packages/plugin-ext/src/main/browser/notebooks/notebook-documents-and-editors-main.ts
@@ -55,7 +55,6 @@ class NotebookAndEditorState {
         const documentDelta = diffSets(before.documents, after.documents);
         const editorDelta = diffMaps(before.textEditors, after.textEditors);
 
-        const newActiveEditor = before.activeEditor !== after.activeEditor ? after.activeEditor : undefined;
         const visibleEditorDelta = diffMaps(before.visibleEditors, after.visibleEditors);
 
         return {
@@ -63,7 +62,7 @@ class NotebookAndEditorState {
             removedDocuments: documentDelta.removed.map(e => e.uri.toComponents()),
             addedEditors: editorDelta.added,
             removedEditors: editorDelta.removed.map(removed => removed.id),
-            newActiveEditor: newActiveEditor,
+            newActiveEditor: after.activeEditor,
             visibleEditors: visibleEditorDelta.added.length === 0 && visibleEditorDelta.removed.length === 0
                 ? undefined
                 : [...after.visibleEditors].map(editor => editor[0])
@@ -114,7 +113,7 @@ export class NotebooksAndEditorsMain implements NotebookDocumentsAndEditorsMain
         // this.WidgetManager.onActiveEditorChanged(() => this.updateState(), this, this.disposables);
         this.notebookEditorService.onDidAddNotebookEditor(async editor => this.handleEditorAdd(editor), this, this.disposables);
         this.notebookEditorService.onDidRemoveNotebookEditor(async editor => this.handleEditorRemove(editor), this, this.disposables);
-        this.notebookEditorService.onDidChangeFocusedEditor(async editor => this.updateState(editor), this, this.disposables);
+        this.notebookEditorService.onDidChangeCurrentEditor(async editor => this.updateState(editor), this, this.disposables);
     }
 
     dispose(): void {
@@ -221,7 +220,7 @@ export class NotebooksAndEditorsMain implements NotebookDocumentsAndEditorsMain
         if (delta.visibleEditors?.length) {
             return false;
         }
-        if (delta.newActiveEditor) {
+        if (delta.newActiveEditor !== undefined) {
             return false;
         }
         return true;
diff --git a/packages/plugin-ext/src/plugin/notebook/notebooks.ts b/packages/plugin-ext/src/plugin/notebook/notebooks.ts
index 5470495d402ec..d31d9554ca2ac 100644
--- a/packages/plugin-ext/src/plugin/notebook/notebooks.ts
+++ b/packages/plugin-ext/src/plugin/notebook/notebooks.ts
@@ -341,7 +341,7 @@ export class NotebooksExtImpl implements NotebooksExt {
                 });
             }
         }
-        if (delta.newActiveEditor !== undefined) {
+        if (delta.newActiveEditor !== undefined && delta.newActiveEditor !== this.activeNotebookEditor?.id) {
             this.onDidChangeActiveNotebookEditorEmitter.fire(this.activeNotebookEditor?.apiEditor);
         }
     }