diff --git a/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/contentassist2/CompletionTests.java b/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/contentassist2/CompletionTests.java
index b3ea0580088..b9080de1bb1 100644
--- a/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/contentassist2/CompletionTests.java
+++ b/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/contentassist2/CompletionTests.java
@@ -982,6 +982,14 @@ public class CompletionTests extends AbstractContentAssistTest {
 				"\"sub1/inc11.h"
 			};
 			assertCompletionResults(fCursorOffset+=4, expected, AbstractContentAssistTest.COMPARE_REP_STRINGS);
+
+			// bug 278967
+			getDocument().replace(fCursorOffset-5, 5, "../");
+			expected= new String[] {
+				"\"../h1/",
+				"\"../h2/",
+			};
+			assertCompletionResults(fCursorOffset-=2, expected, AbstractContentAssistTest.COMPARE_REP_STRINGS);
 		} finally {
 			deleteDir(tempDir);
 		}
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/contentassist/InclusionProposalComputer.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/contentassist/InclusionProposalComputer.java
index db1ec7b27da..05dd50d1e8f 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/contentassist/InclusionProposalComputer.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/contentassist/InclusionProposalComputer.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2008 Wind River Systems, Inc. and others.
+ * Copyright (c) 2008, 2009 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
@@ -279,12 +279,16 @@ public class InclusionProposalComputer implements ICompletionProposalComputer {
 		} else if (prefixPath.hasTrailingSeparator()) {
 			namePrefix= ""; //$NON-NLS-1$
 			prefixPath= prefixPath.removeTrailingSeparator();
-			parent= parent.getFolder(prefixPath);
 		} else {
 			namePrefix= prefixPath.lastSegment();
 			prefixPath= prefixPath.removeLastSegments(1);
-			if (prefixPath.segmentCount() > 0) {
+		}
+		if (prefixPath.segmentCount() > 0) {
+			IPath parentPath = parent.getFullPath().append(prefixPath);
+			if (parentPath.segmentCount() > 0) {
 				parent= parent.getFolder(prefixPath);
+			} else {
+				return;
 			}
 		}
 		if (!parent.exists()) {