diff --git a/org.eclipse.egit.relengtools/src/org/eclipse/egit/internal/relengtools/MapFileCompareEditorInput.java b/org.eclipse.egit.relengtools/src/org/eclipse/egit/internal/relengtools/MapFileCompareEditorInput.java
new file mode 100755
index 0000000..6edb7c2
--- /dev/null
+++ b/org.eclipse.egit.relengtools/src/org/eclipse/egit/internal/relengtools/MapFileCompareEditorInput.java
@@ -0,0 +1,190 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2005 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.egit.internal.relengtools;
+
+import java.lang.reflect.InvocationTargetException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.eclipse.compare.CompareConfiguration;
+import org.eclipse.compare.CompareEditorInput;
+import org.eclipse.compare.ResourceNode;
+import org.eclipse.compare.structuremergeviewer.DiffNode;
+import org.eclipse.compare.structuremergeviewer.Differencer;
+import org.eclipse.compare.structuremergeviewer.IDiffElement;
+import org.eclipse.core.resources.IProject;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.egit.core.GitTag;
+import org.eclipse.jface.viewers.Viewer;
+import org.eclipse.swt.graphics.Image;
+import org.eclipse.swt.widgets.Composite;
+
+/**
+ * This class extends
+ * <code>CompareEditorInput<code>. It defines the input for map file compare editor, which is showed by
+ * <code>MapFileComparePage<code>
+ */
+public class MapFileCompareEditorInput extends CompareEditorInput {
+
+	private MapContentDocument[] documents;
+
+	private DiffNode root;
+
+	private Viewer viewer;
+
+	private MapProject mapProject;
+
+	private IProject[] selectedProjects;
+
+	private String tag; // The proposed tag
+
+	public MapFileCompareEditorInput() {
+		super(new CompareConfiguration());
+		documents = new MapContentDocument[0];
+		root = new DiffNode(Differencer.NO_CHANGE) {
+			@Override
+			public boolean hasChildren() {
+				return true;
+			}
+		};
+		mapProject = null;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see
+	 * org.eclipse.compare.CompareEditorInput#prepareInput(org.eclipse.core.
+	 * runtime.IProgressMonitor)
+	 */
+	@Override
+	protected Object prepareInput(IProgressMonitor monitor)
+			throws InvocationTargetException, InterruptedException {
+		final CompareConfiguration config = getCompareConfiguration();
+		config.setRightEditable(false);
+		config.setLeftEditable(false);
+		config.setRightLabel("Proposed change");
+		config.setLeftLabel("Current content");
+		return root;
+	}
+
+	public void updateInput(IProject[] projects, String tag)
+			throws CoreException {
+		setSelectedProjects(projects);
+		setTag(tag);
+		final MapContentDocument[] docs = constructDocuments();
+		setDocuments(docs);
+		buildTree();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see
+	 * org.eclipse.compare.CompareEditorInput#createDiffViewer(org.eclipse.swt
+	 * .widgets.Composite)
+	 */
+	@Override
+	public Viewer createDiffViewer(Composite parent) {
+		viewer = super.createDiffViewer(parent);
+		viewer.setInput(this);
+		return viewer;
+	}
+
+	public void updateMapProject(MapProject m) {
+		mapProject = m;
+	}
+
+	private void setDocuments(MapContentDocument[] docs) {
+		this.documents = docs;
+	}
+
+	private void buildTree() {
+		if (documents == null || documents.length == 0)
+			return;
+		// Empty the tree
+		if (root.hasChildren()) {
+			final IDiffElement[] children = root.getChildren();
+			for (int i = 0; i < children.length; i++) {
+				root.remove(children[i]);
+			}
+		}
+
+		// rebuild the tree
+		final DiffNode[] diffNodes = new DiffNode[documents.length];
+		for (int i = 0; i < diffNodes.length; i++) {
+			final ResourceNode resourceNode = new ResourceNode(documents[i]
+					.getMapFile().getFile()) {
+				@Override
+				public boolean isEditable() {
+					return false;
+				}
+			};
+
+			diffNodes[i] = new DiffNode(root, Differencer.CHANGE, null,
+					resourceNode, documents[i]) {
+				@Override
+				public Image getImage() {
+					return getLeft().getImage();
+				}
+			};
+		}
+		viewer.refresh();
+	}
+
+	/*
+	 * Returns the map files that will change due to the projects being released
+	 */
+	private MapFile[] getChangedMapFiles() {
+		if (selectedProjects == null || selectedProjects.length == 0)
+			return null;
+		final List projectList = new ArrayList();
+		final GitTag[] tags = mapProject.getTagsFor(selectedProjects);
+		for (int i = 0; i < selectedProjects.length; i++) {
+			if (!tags[i].getName().equals(tag)) {
+				projectList.add(selectedProjects[i]);
+			}
+		}
+		final IProject[] projects = (IProject[]) projectList
+				.toArray(new IProject[projectList.size()]);
+		return mapProject.getMapFilesFor(projects);
+	}
+
+	// Construct the document as the diffNode.
+	private MapContentDocument[] constructDocuments() throws CoreException {
+		final MapFile[] mapFiles = getChangedMapFiles();
+		if (mapFiles == null || mapFiles.length == 0)
+			return null;
+		final MapContentDocument[] docs = new MapContentDocument[mapFiles.length];
+		for (int i = 0; i < mapFiles.length; i++) {
+			docs[i] = new MapContentDocument(mapFiles[i]);
+			for (int j = 0; j < selectedProjects.length; j++) {
+				// update the new content of each selected projects
+				if (mapFiles[i].contains(selectedProjects[j])) {
+					docs[i].updateTag(selectedProjects[j], tag);
+				}
+			}
+		}
+		return docs;
+	}
+
+	private void setSelectedProjects(IProject[] projects) {
+		if (projects != null && projects.length != 0) {
+			selectedProjects = new IProject[projects.length];
+			System.arraycopy(projects, 0, selectedProjects, 0, projects.length);
+		}
+	}
+
+	private void setTag(String t) {
+		this.tag = t;
+	}
+}