diff --git a/core/org.eclipse.cdt.core/ChangeLog b/core/org.eclipse.cdt.core/ChangeLog
index 3bc0cebedb7..12e4165c63f 100644
--- a/core/org.eclipse.cdt.core/ChangeLog
+++ b/core/org.eclipse.cdt.core/ChangeLog
@@ -1,3 +1,14 @@
+2003-09-24 David Inglis
+	
+	* src/org/eclipse/cdt/internal/core/CExtensionInfo.java
+	null should removed attributes.
+	
+	* src/org/eclipse/cdt/internal/core/CDescriptor.java	
+	Fixed bug# 43533
+	
+	* model/org/eclipse/cdt/internal/core/model/Binary.java
+	Help with slow IBinary interface.
+	
 2003-09-22 Bogdan Gheorghe
 
 	Took out old CTags code from CCorePlugin
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/Binary.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/Binary.java
index acbebb57c0b..043108c2bdb 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/Binary.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/model/Binary.java
@@ -24,6 +24,10 @@ import org.eclipse.core.runtime.Path;
 
 public class Binary extends Openable implements IBinary {
 
+	private int fBinType;
+
+	private long fLastModification;
+
 	IBinaryFile binaryFile;
 
 	public Binary(ICElement parent, IFile file, IBinaryFile bin) {
@@ -37,31 +41,19 @@ public class Binary extends Openable implements IBinary {
 	}
 
 	public boolean isSharedLib() {
-		if (binaryFile != null) {
-			return binaryFile.getType() == IBinaryObject.SHARED;
-		}
-		return false;
+		return getType() == IBinaryObject.SHARED;
 	}
 
 	public boolean isExecutable() {
-		if (binaryFile != null) {
-			return binaryFile.getType() == IBinaryObject.EXECUTABLE;
-		}
-		return false;
+		return getType() == IBinaryObject.EXECUTABLE;
 	}
 
 	public boolean isObject() {
-		if (binaryFile != null) {
-			return binaryFile.getType() == IBinaryObject.OBJECT;
-		}
-		return false;
+		return getType() == IBinaryObject.OBJECT;
 	}
 
 	public boolean isCore() {
-		if (binaryFile != null) {
-			return binaryFile.getType() == IBinaryObject.CORE;
-		}
-		return false;
+		return getType() == IBinaryObject.CORE;
 	}
 
 	public boolean hasDebug() {
@@ -84,6 +76,15 @@ public class Binary extends Openable implements IBinary {
 		}
 		return new String[0];
 	}
+	
+	protected int getType() {
+		IResource res = getResource();
+		if (binaryFile != null && (fBinType == 0 || res.getModificationStamp() != fLastModification )) {
+			fLastModification = res.getModificationStamp();
+			fBinType = binaryFile.getType();
+		}
+		return fBinType;
+	}
 
 	public long getText() {
 		if (isObject() || isExecutable() || isSharedLib()) {
diff --git a/core/org.eclipse.cdt.core/src/org/eclipse/cdt/internal/core/CDescriptor.java b/core/org.eclipse.cdt.core/src/org/eclipse/cdt/internal/core/CDescriptor.java
index 2055c0a02ba..d8de5615422 100644
--- a/core/org.eclipse.cdt.core/src/org/eclipse/cdt/internal/core/CDescriptor.java
+++ b/core/org.eclipse.cdt.core/src/org/eclipse/cdt/internal/core/CDescriptor.java
@@ -80,8 +80,7 @@ public class CDescriptor implements ICDescriptor {
 		fProject = project;
 		IPath projectLocation = project.getDescription().getLocation();
 
-		final boolean isDefaultLocation = projectLocation == null;
-		if (isDefaultLocation) {
+		if (projectLocation == null) {
 			projectLocation = getProjectDefaultLocation(project);
 		}
 		IPath descriptionPath = projectLocation.append(DESCRIPTION_FILE_NAME);
@@ -116,8 +115,7 @@ public class CDescriptor implements ICDescriptor {
 		fProject = project;
 		IPath projectLocation = project.getDescription().getLocation();
 
-		final boolean isDefaultLocation = projectLocation == null;
-		if (isDefaultLocation) {
+		if (projectLocation == null) {
 			projectLocation = getProjectDefaultLocation(project);
 		}
 		IPath descriptionPath = projectLocation.append(DESCRIPTION_FILE_NAME);
@@ -133,8 +131,7 @@ public class CDescriptor implements ICDescriptor {
 		fProject = project;
 		IPath projectLocation = project.getDescription().getLocation();
 
-		final boolean isDefaultLocation = projectLocation == null;
-		if (isDefaultLocation) {
+		if (projectLocation == null) {
 			projectLocation = getProjectDefaultLocation(project);
 		}
 		IPath descriptionPath = projectLocation.append(DESCRIPTION_FILE_NAME);
@@ -160,7 +157,13 @@ public class CDescriptor implements ICDescriptor {
 			Document document = parser.parse(file);
 			Node node = document.getFirstChild();
 			if (node.getNodeName().equals(PROJECT_DESCRIPTION)) {
-				return readProjectDescription(node);
+				String ownerID = node.getAttributes().getNamedItem("id").getNodeValue();
+				if ( ownerID != null) {
+					readProjectDescription(node);
+					return ownerID;
+				}
+				IStatus status = new Status(IStatus.ERROR, CCorePlugin.PLUGIN_ID, -1, "Missing owner id", null);
+				throw new CoreException(status);
 			}
 			IStatus status = new Status(IStatus.ERROR, CCorePlugin.PLUGIN_ID, -1, "Missing cdtproject element", null);
 			throw new CoreException(status);
@@ -316,30 +319,35 @@ public class CDescriptor implements ICDescriptor {
 		return s.toString("UTF8"); //$NON-NLS-1$		
 	}
 
-	private String readProjectDescription(Node node) throws CoreException {
+	private void readProjectDescription(Node node) {
 		Node childNode;
 		ArrayList pathEntries = new ArrayList();
-		String ownerID = node.getAttributes().getNamedItem("id").getNodeValue();
 		NodeList list = node.getChildNodes();
 		for (int i = 0; i < list.getLength(); i++) {
 			childNode = list.item(i);
-			if ( childNode.getNodeType() == Node.ELEMENT_NODE ) {
+			if (childNode.getNodeType() == Node.ELEMENT_NODE) {
 				if (childNode.getNodeName().equals(PROJECT_EXTENSION)) {
-					//decodeProjectExtension((Element)node);
-					decodeProjectExtension((Element)childNode);
+					try {
+						decodeProjectExtension((Element) childNode);
+					} catch (CoreException e) {
+						CCorePlugin.log(e);
+					}
 				} else if (childNode.getNodeName().equals(PATH_ENTRY)) {
-					//ICPathEntry entry = decodePathEntry((Element)node);
-					ICPathEntry entry = decodePathEntry((Element)childNode);
-					if (entry != null) {
-						pathEntries.add(entry);
+					try {
+						pathEntries.add(decodePathEntry((Element) childNode));
+					} catch (CoreException e) {
+						CCorePlugin.log(e);
 					}
 				} else if (childNode.getNodeName().equals(PROJECT_DATA)) {
-					decodeProjectData((Element)childNode);
+					try {
+						decodeProjectData((Element)childNode);
+					} catch (CoreException e) {
+						CCorePlugin.log(e);
+					}
 				}
 			}
 		}
 		fPathEntries = (ICPathEntry[]) pathEntries.toArray(new ICPathEntry[0]);
-		return ownerID;
 	}
 
 	private void decodeProjectExtension(Element element) throws CoreException {
@@ -542,6 +550,9 @@ public class CDescriptor implements ICDescriptor {
 		IPluginRegistry pluginRegistry = Platform.getPluginRegistry();
 		IExtensionPoint extensionPoint = pluginRegistry.getExtensionPoint(ext.getExtension());
 		IExtension extension = extensionPoint.getExtension(ext.getID());
+		if ( extension == null) {
+			throw new CoreException(new Status(IStatus.ERROR, CCorePlugin.PLUGIN_ID, -1, "Extension provider not found.", null));
+		}
 		IConfigurationElement element[] = extension.getConfigurationElements();
 		for (int i = 0; i < element.length; i++) {
 			if (element[i].getName().equalsIgnoreCase("cextension")) {
diff --git a/core/org.eclipse.cdt.core/src/org/eclipse/cdt/internal/core/CExtensionInfo.java b/core/org.eclipse.cdt.core/src/org/eclipse/cdt/internal/core/CExtensionInfo.java
index e4fd954eed0..7d9e146bb91 100644
--- a/core/org.eclipse.cdt.core/src/org/eclipse/cdt/internal/core/CExtensionInfo.java
+++ b/core/org.eclipse.cdt.core/src/org/eclipse/cdt/internal/core/CExtensionInfo.java
@@ -15,13 +15,17 @@ import java.util.HashMap;
 public class CExtensionInfo {
 
 	protected HashMap attribMap = new HashMap(4);
-	
+
 	protected HashMap getAttributes() {
 		return attribMap;
 	}
 
 	public void setAttribute(String key, String value) {
-		attribMap.put(key, value);
+		if (value == null) {
+			attribMap.remove(key);
+		} else {
+			attribMap.put(key, value);
+		}
 	}
 
 	public String getAttribute(String key) {