diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/FileLanguageMappingPropertyPage.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/FileLanguageMappingPropertyPage.java
index fa893343dcd..459d6bd97c0 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/FileLanguageMappingPropertyPage.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/FileLanguageMappingPropertyPage.java
@@ -72,6 +72,7 @@ public class FileLanguageMappingPropertyPage extends PropertyPage {
 	private Table fTable;
 	private ILanguage[] fLanguages;
 	private Map fLanguageIds;
+	private boolean fHasChanges;
 	
 	public FileLanguageMappingPropertyPage() {
 		super();
@@ -178,6 +179,7 @@ public class FileLanguageMappingPropertyPage extends PropertyPage {
 							String selectedLanguage = ((String[]) combo.getData())[index];
 							LanguageTableData data = (LanguageTableData) item.getData();
 							data.languageId = selectedLanguage;
+							fHasChanges = true;
 							
 							try {
 								refreshMappings();
@@ -307,6 +309,10 @@ public class FileLanguageMappingPropertyPage extends PropertyPage {
 
 	public boolean performOk() {
 		try {
+			if (!fHasChanges) {
+				return true;
+			}
+			
 			IFile file = getFile();
 			IProject project = file.getProject();
 			LanguageManager manager = LanguageManager.getInstance();
@@ -330,6 +336,7 @@ public class FileLanguageMappingPropertyPage extends PropertyPage {
 			}
 			config.setFileMappings(file, mappings);
 			manager.storeLanguageMappingConfiguration(file);
+			fHasChanges = false;
 			return true;
 		} catch (CoreException e) {
 			CCorePlugin.log(e);
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/LanguageMappingWidget.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/LanguageMappingWidget.java
index e9cd419f6a2..0c810983dd9 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/LanguageMappingWidget.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/LanguageMappingWidget.java
@@ -44,6 +44,8 @@ public abstract class LanguageMappingWidget {
 	
 	protected Set fOverriddenContentTypes;
 	
+	private boolean fIsChanged;
+	
 	public LanguageMappingWidget() {
 		fOverriddenFont = JFaceResources.getFontRegistry().getItalic(JFaceResources.DIALOG_FONT);
 		fOverriddenContentTypes = Collections.EMPTY_SET;
@@ -91,6 +93,14 @@ public abstract class LanguageMappingWidget {
 		fChild = child;
 	}
 	
+	public boolean isChanged() {
+		return fIsChanged;
+	}
+
+	public void setChanged(boolean changed) {
+		fIsChanged = changed;
+	}
+	
 	protected void createHeader(Composite parent, String description) {
 		Link link = new Link(fContents, SWT.NONE);
 		link.setText(description);
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/ProjectLanguageMappingPropertyPage.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/ProjectLanguageMappingPropertyPage.java
index b5aaee55a26..86e1ee96ddc 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/ProjectLanguageMappingPropertyPage.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/ProjectLanguageMappingPropertyPage.java
@@ -161,9 +161,14 @@ public class ProjectLanguageMappingPropertyPage extends PropertyPage {
 
 	public boolean performOk() {
 		try {
+			if (!fMappingWidget.isChanged()) {
+				return true;
+			}
+			
 			fMappings.setContentTypeMappings(fMappingWidget.getContentTypeMappings());
 			IContentType[] affectedContentTypes = fMappingWidget.getAffectedContentTypes();
 			LanguageManager.getInstance().storeLanguageMappingConfiguration(getProject(), affectedContentTypes);
+			fMappingWidget.setChanged(false);
 			return true;
 		} catch (CoreException e) {
 			CCorePlugin.log(e);
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/ProjectLanguageMappingWidget.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/ProjectLanguageMappingWidget.java
index 49c0c460758..3c624d3f3f9 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/ProjectLanguageMappingWidget.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/ProjectLanguageMappingWidget.java
@@ -133,6 +133,7 @@ public class ProjectLanguageMappingWidget extends LanguageMappingWidget {
 						fConfigurationContentTypeMappings.put(configuration, contentTypeMappings);
 					}
 					contentTypeMappings.put(contentType, language);
+					setChanged(true);
 					
 					IContentTypeManager contentTypeManager = Platform.getContentTypeManager();
 					fAffectedContentTypes.add(contentTypeManager.getContentType(contentType));
@@ -168,6 +169,10 @@ public class ProjectLanguageMappingWidget extends LanguageMappingWidget {
 					IContentTypeManager contentTypeManager = Platform.getContentTypeManager();
 					fAffectedContentTypes.add(contentTypeManager.getContentType(contentType));
 				}
+				
+				if (selection.length > 0) {
+					setChanged(true);
+				}
 
 				refreshMappings();
 			}
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/WorkspaceLanguageMappingPreferencePage.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/WorkspaceLanguageMappingPreferencePage.java
index 8670c0bfb16..10d7a0791c9 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/WorkspaceLanguageMappingPreferencePage.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/WorkspaceLanguageMappingPreferencePage.java
@@ -69,11 +69,16 @@ public class WorkspaceLanguageMappingPreferencePage extends PreferencePage imple
 	
 	public boolean performOk() {
 		try {
+			if (!fMappingWidget.isChanged()) {
+				return true;
+			}
+			
 			IContentType[] affectedContentTypes = fMappingWidget.getAffectedContentTypes();
 			LanguageManager manager = LanguageManager.getInstance();
 			WorkspaceLanguageConfiguration config = manager.getWorkspaceLanguageConfiguration();
 			config.setWorkspaceMappings(fMappingWidget.getContentTypeMappings());
 			manager.storeWorkspaceLanguageConfiguration(affectedContentTypes);
+			fMappingWidget.setChanged(false);
 			return true;
 		} catch (CoreException e) {
 			CCorePlugin.log(e);
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/WorkspaceLanguageMappingWidget.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/WorkspaceLanguageMappingWidget.java
index bd6eb4511a9..e898b98f938 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/WorkspaceLanguageMappingWidget.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/language/WorkspaceLanguageMappingWidget.java
@@ -100,6 +100,7 @@ public class WorkspaceLanguageMappingWidget extends LanguageMappingWidget {
 						String contentType = dialog.getContentTypeID();
 						String language = dialog.getLanguageID();
 						fContentTypeMappings.put(contentType, language);
+						setChanged(true);
 						IContentTypeManager contentTypeManager = Platform.getContentTypeManager();
 						fAffectedContentTypes.add(contentTypeManager.getContentType(contentType));
 						refreshMappings();
@@ -123,6 +124,10 @@ public class WorkspaceLanguageMappingWidget extends LanguageMappingWidget {
 						IContentTypeManager contentTypeManager = Platform.getContentTypeManager();
 						fAffectedContentTypes.add(contentTypeManager.getContentType(contentType));
 					}
+					
+					if (selection.length > 0) {
+						setChanged(true);
+					}
 	
 					refreshMappings();
 				}