diff --git a/org.eclipse.jdt.debug.ui/ui/org/eclipse/jdt/internal/debug/ui/variables/ColumnPresentationAdapterFactory.java b/org.eclipse.jdt.debug.ui/ui/org/eclipse/jdt/internal/debug/ui/variables/ColumnPresentationAdapterFactory.java
index 8eb3802f74..7e16743f9e 100644
--- a/org.eclipse.jdt.debug.ui/ui/org/eclipse/jdt/internal/debug/ui/variables/ColumnPresentationAdapterFactory.java
+++ b/org.eclipse.jdt.debug.ui/ui/org/eclipse/jdt/internal/debug/ui/variables/ColumnPresentationAdapterFactory.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2006, 2015 IBM Corporation and others.
+ * Copyright (c) 2006, 2026 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -16,6 +16,7 @@
 import org.eclipse.core.runtime.IAdapterFactory;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.IColumnPresentationFactory;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.IElementEditor;
+import org.eclipse.debug.ui.IWatchExpressionCellEditorFactory;
 import org.eclipse.jdt.debug.core.IJavaStackFrame;
 import org.eclipse.jdt.debug.core.IJavaVariable;
 
@@ -28,6 +29,7 @@ public class ColumnPresentationAdapterFactory implements IAdapterFactory {
 
 	private static final IColumnPresentationFactory fgColumnPresentation = new JavaVariableColumnPresentationFactory();
 	private static final IElementEditor fgEEJavaVariable = new JavaVariableEditor();
+	private static final IWatchExpressionCellEditorFactory fgWatchExpressionCellEditorFactory = new JavaWatchExpressionCellEditorFactory();
 
 	/* (non-Javadoc)
 	 * @see org.eclipse.core.runtime.IAdapterFactory#getAdapter(java.lang.Object, java.lang.Class)
@@ -44,6 +46,9 @@ public <T> T getAdapter(Object adaptableObject, Class<T> adapterType) {
 			if (IColumnPresentationFactory.class.equals(adapterType)) {
 				return (T) fgColumnPresentation;
 			}
+			if (IWatchExpressionCellEditorFactory.class.equals(adapterType)) {
+				return (T) fgWatchExpressionCellEditorFactory;
+			}
 		}
 		return null;
 	}
@@ -55,7 +60,8 @@ public <T> T getAdapter(Object adaptableObject, Class<T> adapterType) {
 	public Class<?>[] getAdapterList() {
 		return new Class[]{
 				IColumnPresentationFactory.class,
-				IElementEditor.class};
+				IElementEditor.class,
+				IWatchExpressionCellEditorFactory.class};
 	}
 
 }
diff --git a/org.eclipse.jdt.debug.ui/ui/org/eclipse/jdt/internal/debug/ui/variables/JDISourceViewerCellEditor.java b/org.eclipse.jdt.debug.ui/ui/org/eclipse/jdt/internal/debug/ui/variables/JDISourceViewerCellEditor.java
new file mode 100644
index 0000000000..85f0a35259
--- /dev/null
+++ b/org.eclipse.jdt.debug.ui/ui/org/eclipse/jdt/internal/debug/ui/variables/JDISourceViewerCellEditor.java
@@ -0,0 +1,196 @@
+/*******************************************************************************
+ * Copyright (c) 2026 IBM Corporation.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.jdt.internal.debug.ui.variables;
+
+import org.eclipse.core.commands.AbstractHandler;
+import org.eclipse.core.commands.ExecutionEvent;
+import org.eclipse.core.commands.IHandler;
+import org.eclipse.jdt.internal.debug.ui.JDIDebugUIPlugin;
+import org.eclipse.jdt.internal.debug.ui.JDISourceViewer;
+import org.eclipse.jdt.internal.debug.ui.contentassist.CurrentFrameContext;
+import org.eclipse.jdt.internal.debug.ui.contentassist.JavaDebugContentAssistProcessor;
+import org.eclipse.jdt.internal.debug.ui.display.DisplayViewerConfiguration;
+import org.eclipse.jdt.ui.text.IJavaPartitions;
+import org.eclipse.jface.text.Document;
+import org.eclipse.jface.text.contentassist.ICompletionListener;
+import org.eclipse.jface.text.contentassist.ICompletionProposal;
+import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
+import org.eclipse.jface.text.source.ContentAssistantFacade;
+import org.eclipse.jface.text.source.ISourceViewer;
+import org.eclipse.jface.viewers.CellEditor;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.events.FocusAdapter;
+import org.eclipse.swt.events.FocusEvent;
+import org.eclipse.swt.widgets.Composite;
+import org.eclipse.swt.widgets.Control;
+import org.eclipse.ui.PlatformUI;
+import org.eclipse.ui.handlers.IHandlerActivation;
+import org.eclipse.ui.handlers.IHandlerService;
+import org.eclipse.ui.texteditor.ITextEditorActionDefinitionIds;
+
+/**
+ * A {@link CellEditor} for the Expressions view that wraps a {@link JDISourceViewer} configured with Java content assist.
+ */
+public class JDISourceViewerCellEditor extends CellEditor {
+
+	private JDISourceViewer fViewer;
+	private String fValue = ""; //$NON-NLS-1$
+	/** Tracks whether the content-assist proposal popup is currently open. */
+	private boolean fProposalPopupOpen = false;
+	private IHandlerService fHandlerService;
+	private IHandler fContentAssistHandler;
+	private IHandlerActivation fContentAssistActivation;
+
+	public JDISourceViewerCellEditor(Composite parent) {
+		super(parent, SWT.NONE);
+	}
+
+	@Override
+	protected Control createControl(Composite parent) {
+		fViewer = new JDISourceViewer(parent, null, SWT.BORDER | SWT.SINGLE | SWT.LEFT_TO_RIGHT);
+
+		Document document = new Document();
+		JDIDebugUIPlugin.getDefault().getJavaTextTools().setupJavaDocumentPartitioner(document, IJavaPartitions.JAVA_PARTITIONING);
+
+		fViewer.setInput(document);
+		fViewer.configure(new DisplayViewerConfiguration() {
+			@Override
+			public IContentAssistProcessor getContentAssistantProcessor() {
+				return new JavaDebugContentAssistProcessor(new CurrentFrameContext());
+			}
+		});
+		fViewer.setEditable(true);
+
+		ContentAssistantFacade facade = fViewer.getContentAssistantFacade();
+		if (facade != null) {
+			facade.addCompletionListener(new ICompletionListener() {
+				@Override
+				public void assistSessionStarted(org.eclipse.jface.text.contentassist.ContentAssistEvent event) {
+					fProposalPopupOpen = true;
+				}
+				@Override
+				public void assistSessionEnded(org.eclipse.jface.text.contentassist.ContentAssistEvent event) {
+					fProposalPopupOpen = false;
+				}
+				@Override
+				public void selectionChanged(ICompletionProposal proposal, boolean smartToggle) {
+					// not needed
+				}
+			});
+		}
+
+		fContentAssistHandler = new AbstractHandler() {
+			@Override
+			public Object execute(ExecutionEvent event) throws org.eclipse.core.commands.ExecutionException {
+				fViewer.doOperation(ISourceViewer.CONTENTASSIST_PROPOSALS);
+				return null;
+			}
+		};
+		fHandlerService = PlatformUI.getWorkbench().getAdapter(IHandlerService.class);
+
+		fViewer.getTextWidget().addFocusListener(new FocusAdapter() {
+			@Override
+			public void focusGained(FocusEvent e) {
+				activateContentAssistHandler();
+			}
+			@Override
+			public void focusLost(FocusEvent e) {
+				deactivateContentAssistHandler();
+				if (!fProposalPopupOpen) {
+					JDISourceViewerCellEditor.this.focusLost();
+				}
+			}
+		});
+
+		fViewer.appendVerifyKeyListener(e -> {
+			if (!e.doit) {
+				return;
+			}
+			if (e.keyCode == ' ' && (e.stateMask & SWT.CTRL) != 0) {
+				fViewer.doOperation(ISourceViewer.CONTENTASSIST_PROPOSALS);
+				e.doit = false;
+			} else if (!fProposalPopupOpen) {
+				if (e.keyCode == SWT.CR && (e.stateMask & SWT.SHIFT) == 0) {
+					fireApplyEditorValue();
+					deactivate();
+					e.doit = false;
+				} else if (e.keyCode == SWT.ESC) {
+					fireCancelEditor();
+					e.doit = false;
+				}
+			}
+		});
+
+		return fViewer.getControl();
+	}
+
+	@Override
+	protected Object doGetValue() {
+		if (fViewer != null && fViewer.getDocument() != null) {
+			return fViewer.getDocument().get();
+		}
+		return fValue;
+	}
+
+	@Override
+	protected boolean dependsOnExternalFocusListener() {
+		return false;
+	}
+
+	@Override
+	protected void doSetFocus() {
+		if (fViewer != null) {
+			fViewer.getTextWidget().setFocus();
+		}
+	}
+
+	@Override
+	protected void doSetValue(Object value) {
+		fValue = (value == null) ? "" : value.toString(); //$NON-NLS-1$
+		if (fViewer != null && fViewer.getDocument() != null) {
+			fViewer.getDocument().set(fValue);
+			// Move cursor to end
+			fViewer.getTextWidget().setCaretOffset(fValue.length());
+		}
+	}
+
+	@Override
+	public void deactivate() {
+		deactivateContentAssistHandler();
+		super.deactivate();
+	}
+
+	@Override
+	public void dispose() {
+		deactivateContentAssistHandler();
+		if (fViewer != null) {
+			fViewer.dispose();
+		}
+		super.dispose();
+	}
+
+	private void activateContentAssistHandler() {
+		if (fHandlerService != null && fContentAssistActivation == null) {
+			fContentAssistActivation = fHandlerService.activateHandler(ITextEditorActionDefinitionIds.CONTENT_ASSIST_PROPOSALS, fContentAssistHandler);
+		}
+	}
+
+	private void deactivateContentAssistHandler() {
+		if (fHandlerService != null && fContentAssistActivation != null) {
+			fHandlerService.deactivateHandler(fContentAssistActivation);
+			fContentAssistActivation = null;
+		}
+	}
+
+}
diff --git a/org.eclipse.jdt.debug.ui/ui/org/eclipse/jdt/internal/debug/ui/variables/JavaWatchExpressionCellEditorFactory.java b/org.eclipse.jdt.debug.ui/ui/org/eclipse/jdt/internal/debug/ui/variables/JavaWatchExpressionCellEditorFactory.java
new file mode 100644
index 0000000000..c1ce65f37c
--- /dev/null
+++ b/org.eclipse.jdt.debug.ui/ui/org/eclipse/jdt/internal/debug/ui/variables/JavaWatchExpressionCellEditorFactory.java
@@ -0,0 +1,52 @@
+/*******************************************************************************
+ * Copyright (c) 2026 IBM Corporation.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.jdt.internal.debug.ui.variables;
+
+import java.util.Optional;
+
+import org.eclipse.debug.ui.IWatchExpressionCellEditorFactory;
+import org.eclipse.jdt.internal.debug.ui.JDIDebugUIPlugin;
+import org.eclipse.jdt.internal.debug.ui.contentassist.CurrentFrameContext;
+import org.eclipse.jdt.internal.debug.ui.contentassist.JavaDebugContentAssistProcessor;
+import org.eclipse.jdt.internal.debug.ui.display.DisplayViewerConfiguration;
+import org.eclipse.jdt.ui.text.IJavaPartitions;
+import org.eclipse.jface.text.IDocument;
+import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
+import org.eclipse.jface.text.source.SourceViewer;
+import org.eclipse.jface.viewers.CellEditor;
+import org.eclipse.swt.widgets.Composite;
+
+public class JavaWatchExpressionCellEditorFactory implements IWatchExpressionCellEditorFactory {
+
+	@Override
+	public Optional<CellEditor> createCellEditor(Composite parent) {
+		return Optional.of(new JDISourceViewerCellEditor(parent));
+	}
+
+	@Override
+	public void configureSourceViewer(SourceViewer viewer) {
+		viewer.configure(new DisplayViewerConfiguration() {
+			@Override
+			public IContentAssistProcessor getContentAssistantProcessor() {
+				return new JavaDebugContentAssistProcessor(new CurrentFrameContext());
+			}
+		});
+	}
+
+	@Override
+	public void prepareDocument(IDocument document) {
+		JDIDebugUIPlugin.getDefault().getJavaTextTools()
+				.setupJavaDocumentPartitioner(document, IJavaPartitions.JAVA_PARTITIONING);
+	}
+}