diff --git a/qt/org.eclipse.cdt.qt.core/plugin.xml b/qt/org.eclipse.cdt.qt.core/plugin.xml
index aa0f7908f27..08c187ec49d 100644
--- a/qt/org.eclipse.cdt.qt.core/plugin.xml
+++ b/qt/org.eclipse.cdt.qt.core/plugin.xml
@@ -91,4 +91,13 @@
             <language-scope id="org.eclipse.cdt.core.g++"/>
         </provider>
     </extension>
+    <extension point="org.eclipse.core.expressions.definitions">
+        <definition id="org.eclipse.cdt.qt.core.isQtProject">
+            <with variable="projectNatures">
+                    <iterate operator="or">
+                        <equals value="org.eclipse.cdt.qt.core.qtNature"/>
+                    </iterate>
+            </with>
+        </definition>
+    </extension>
 </plugin>
diff --git a/qt/org.eclipse.cdt.qt.core/src/org/eclipse/cdt/qt/core/QtNature.java b/qt/org.eclipse.cdt.qt.core/src/org/eclipse/cdt/qt/core/QtNature.java
index a6f9a7a8748..cb7d2610980 100644
--- a/qt/org.eclipse.cdt.qt.core/src/org/eclipse/cdt/qt/core/QtNature.java
+++ b/qt/org.eclipse.cdt.qt.core/src/org/eclipse/cdt/qt/core/QtNature.java
@@ -14,6 +14,7 @@ import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IProjectDescription;
 import org.eclipse.core.resources.IProjectNature;
 import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IProgressMonitor;
 
 public class QtNature implements IProjectNature {
 	private static final String ID = "org.eclipse.cdt.qt.core.qtNature";
@@ -27,7 +28,7 @@ public class QtNature implements IProjectNature {
 		}
 	}
 
-	public static void addNature(IProject project) throws CoreException {
+	public static void addNature(IProject project, IProgressMonitor monitor) throws CoreException {
 		if (project.isOpen()) {
 			if (hasNature(project))
 				return;
@@ -35,8 +36,10 @@ public class QtNature implements IProjectNature {
 			IProjectDescription desc = project.getDescription();
 			String[] oldIds = desc.getNatureIds();
 			String[] newIds = new String[oldIds.length + 1];
+			System.arraycopy(oldIds, 0, newIds, 0, oldIds.length);
 			newIds[oldIds.length] = ID;
 			desc.setNatureIds(newIds);
+			project.setDescription(desc, monitor);
 		}
 	}
 	
diff --git a/qt/org.eclipse.cdt.qt.tests/src/org/eclipse/cdt/qt/tests/BaseQtTestCase.java b/qt/org.eclipse.cdt.qt.tests/src/org/eclipse/cdt/qt/tests/BaseQtTestCase.java
index b06355f9e39..2c023b29ba2 100644
--- a/qt/org.eclipse.cdt.qt.tests/src/org/eclipse/cdt/qt/tests/BaseQtTestCase.java
+++ b/qt/org.eclipse.cdt.qt.tests/src/org/eclipse/cdt/qt/tests/BaseQtTestCase.java
@@ -18,6 +18,7 @@ import org.eclipse.cdt.core.testplugin.util.TestSourceReader;
 import org.eclipse.cdt.qt.core.QtNature;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IProject;
+import org.eclipse.core.runtime.NullProgressMonitor;
 
 public class BaseQtTestCase extends BaseTestCase {
 
@@ -46,7 +47,7 @@ public class BaseQtTestCase extends BaseTestCase {
 
 		fCProject = CProjectHelper.createCCProject(projectName, "bin", IPDOMManager.ID_FAST_INDEXER);
 		fProject = fCProject.getProject();
-		QtNature.addNature(fProject);
+		QtNature.addNature(fProject, new NullProgressMonitor());
 		fIndex = CCorePlugin.getIndexManager().getIndex(fCProject);
 
 		indexQObject_h();