diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/rewrite/commenthandler/ASTCommenter.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/rewrite/commenthandler/ASTCommenter.java
index 12505df3796..4398eb261f7 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/rewrite/commenthandler/ASTCommenter.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/rewrite/commenthandler/ASTCommenter.java
@@ -15,12 +15,18 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.TreeMap;
 
+import org.eclipse.cdt.core.CCorePlugin;
+import org.eclipse.cdt.core.CProjectNature;
 import org.eclipse.cdt.core.dom.ast.IASTComment;
 import org.eclipse.cdt.core.dom.ast.IASTDeclaration;
 import org.eclipse.cdt.core.dom.ast.IASTNode;
 import org.eclipse.cdt.core.dom.ast.IASTPreprocessorStatement;
 import org.eclipse.cdt.core.dom.ast.IASTTranslationUnit;
 import org.eclipse.cdt.internal.core.dom.rewrite.util.OffsetHelper;
+import org.eclipse.cdt.internal.core.model.CProject;
+import org.eclipse.core.resources.IProject;
+import org.eclipse.core.resources.ResourcesPlugin;
+import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.Path;
 import org.eclipse.core.runtime.Platform;
@@ -137,9 +143,12 @@ public class ASTCommenter {
 	}
 
 	private static boolean isInWorkspace(IASTNode node) {
-		IPath workspacePath = Platform.getLocation();
+		IProject[] projects = ResourcesPlugin.getWorkspace().getRoot().getProjects();
 		IPath nodePath = new Path(node.getContainingFilename());
-		return workspacePath.isPrefixOf(nodePath);
+		for (IProject project : projects) {
+			if(project.getLocation().isPrefixOf(nodePath)) return true;
+		}
+		return false;
 	}