diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/model/CoreModelUtil.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/model/CoreModelUtil.java
index 2f0801a2f38..90fed85f2e8 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/model/CoreModelUtil.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/model/CoreModelUtil.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2002, 2009 QNX Software Systems and others.
+ * Copyright (c) 2002, 2010 QNX Software Systems 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
@@ -550,6 +550,7 @@ public class CoreModelUtil {
 	 */
 	public static ITranslationUnit findTranslationUnitForLocation(IPath location, ICProject preferredProject) throws CModelException {
 		IFile[] files= ResourceLookup.findFilesForLocation(location);
+		ResourceLookup.sortFilesByRelevance(files, preferredProject != null ? preferredProject.getProject() : null);
 		boolean oneExisting= false;
 		if (files.length > 0) {
 			for (IFile file : files) {
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/includebrowser/IBViewPart.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/includebrowser/IBViewPart.java
index 777811ca5d3..2ae58cf8759 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/includebrowser/IBViewPart.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/includebrowser/IBViewPart.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2006, 2008 Wind River Systems, Inc. and others.
+ * Copyright (c) 2006, 2010 Wind River Systems, Inc. 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
@@ -84,6 +84,7 @@ import org.eclipse.cdt.core.index.IIndexFileLocation;
 import org.eclipse.cdt.core.index.IndexLocationFactory;
 import org.eclipse.cdt.core.model.CModelException;
 import org.eclipse.cdt.core.model.CoreModel;
+import org.eclipse.cdt.core.model.CoreModelUtil;
 import org.eclipse.cdt.core.model.ICElement;
 import org.eclipse.cdt.core.model.ICProject;
 import org.eclipse.cdt.core.model.ITranslationUnit;
@@ -221,15 +222,27 @@ public class IBViewPart extends ViewPart
 					index.acquireReadLock();
 					try {
 						if (!IndexUI.isIndexed(index, input)) {
-							final String msg = IndexUI.getFileNotIndexedMessage(input);
-							display.asyncExec(new Runnable() {
-								public void run() {
-									if (fTreeViewer.getInput() == input) {
-										setMessage(msg);
-										fTreeViewer.setInput(null);
+							// Bug 306879: Try to find an alternative translation unit for the file by the location.
+							final ITranslationUnit alt= CoreModelUtil.findTranslationUnitForLocation(input.getLocation(), input.getCProject());
+							if (alt != null && IndexUI.isIndexed(index, alt)) {
+								display.asyncExec(new Runnable() {
+									public void run() {
+										if (fTreeViewer.getInput() == input) {
+											setInput(alt);
+										}
 									}
-								}
-							});
+								});
+							} else {
+								final String msg = IndexUI.getFileNotIndexedMessage(input);
+								display.asyncExec(new Runnable() {
+									public void run() {
+										if (fTreeViewer.getInput() == input) {
+											setMessage(msg);
+											fTreeViewer.setInput(null);
+										}
+									}
+								});
+							}
 						}
 						return Status.OK_STATUS;
 					} finally {
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/viewsupport/IndexUI.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/viewsupport/IndexUI.java
index d64e606dc72..12e793bfda3 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/viewsupport/IndexUI.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/viewsupport/IndexUI.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2009 Wind River Systems, Inc. and others.
+ * Copyright (c) 2007, 2010 Wind River Systems, Inc. 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
@@ -33,7 +33,6 @@ import org.eclipse.ui.IEditorInput;
 
 import org.eclipse.cdt.core.CCorePlugin;
 import org.eclipse.cdt.core.IPositionConverter;
-import org.eclipse.cdt.core.dom.IName;
 import org.eclipse.cdt.core.dom.ast.DOMException;
 import org.eclipse.cdt.core.dom.ast.IASTDeclarator;
 import org.eclipse.cdt.core.dom.ast.IASTExpression;
@@ -329,10 +328,19 @@ public class IndexUI {
 		return null;
 	}
 	
-	public static ITranslationUnit getTranslationUnit(ICProject cproject, IName name) {
+	public static ITranslationUnit getTranslationUnit(ICProject cproject, IASTName name) {
 		return getTranslationUnit(cproject, name.getFileLocation());
 	}
 
+	public static ITranslationUnit getTranslationUnit(ICProject cproject, IIndexName name) {
+		try {
+			return CoreModelUtil.findTranslationUnitForLocation(name.getFile().getLocation(), cproject);
+		} catch (CoreException e) {
+			CUIPlugin.log(e);
+		}
+		return null;
+	}
+
 	private static ITranslationUnit getTranslationUnit(ICProject cproject, final IASTFileLocation fileLocation) {
 		if (fileLocation != null) {
 			IPath path= Path.fromOSString(fileLocation.getFileName());