diff --git a/debug/org.eclipse.cdt.debug.core/ChangeLog b/debug/org.eclipse.cdt.debug.core/ChangeLog
index 42399995b3b..6af66f616be 100644
--- a/debug/org.eclipse.cdt.debug.core/ChangeLog
+++ b/debug/org.eclipse.cdt.debug.core/ChangeLog
@@ -1,3 +1,10 @@
+2005-06-09 Mikhail Khodjaiants
+	Bug 94139: User-defined register groups.
+	Support fo the "Restore Default Register Groups" action.
+	* ICDebugTarget.java
+	* CRegisterManager.java
+	* CDebugTarget.java
+
 2005-06-07 Mikhail Khodjaiants
 	Bug 94139: User-defined register groups.
 	Support fo the "Edit Register Group" action.
diff --git a/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/core/model/ICDebugTarget.java b/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/core/model/ICDebugTarget.java
index 50c74ed150d..35888501293 100644
--- a/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/core/model/ICDebugTarget.java
+++ b/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/core/model/ICDebugTarget.java
@@ -126,4 +126,12 @@ public interface ICDebugTarget extends IDebugTarget,
 	 * @since 3.0
 	 */
 	public void modifyRegisterGroup( IPersistableRegisterGroup group, IRegisterDescriptor[] descriptors );
+
+
+	/**
+	 * Removes all user-defined register groups and restores the hardware groups.
+	 * 
+	 * @since 3.0
+	 */
+	public void restoreDefaultRegisterGroups();
 }
diff --git a/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/internal/core/CRegisterManager.java b/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/internal/core/CRegisterManager.java
index 4333a00b210..fe7ac771d54 100644
--- a/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/internal/core/CRegisterManager.java
+++ b/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/internal/core/CRegisterManager.java
@@ -80,7 +80,18 @@ public class CRegisterManager {
 	}
 
 	public void dispose() {
-		removeAllRegisterGroups();
+		DebugPlugin.getDefault().asyncExec( 
+				new Runnable() {
+					public void run() {
+						synchronized( fRegisterGroups ) {
+							Iterator it = fRegisterGroups.iterator();
+							while( it.hasNext() ) {
+								((CRegisterGroup)it.next()).dispose();
+							}
+							fRegisterGroups.clear();
+						}
+					}
+				} );
 	}
 
 	public IRegisterDescriptor[] getAllRegisterDescriptors() throws DebugException {
@@ -154,6 +165,23 @@ public class CRegisterManager {
 			} );
 	}
 
+	public void restoreDefaults() {
+		DebugPlugin.getDefault().asyncExec( 
+				new Runnable() {
+					public void run() {
+						synchronized( fRegisterGroups ) {
+							Iterator it = fRegisterGroups.iterator();
+							while( it.hasNext() ) {
+								((CRegisterGroup)it.next()).dispose();
+							}
+							fRegisterGroups.clear();
+							initializeDefaults();
+						}
+						getDebugTarget().fireChangeEvent( DebugEvent.CONTENT );
+					}
+				} );
+	}
+
 	private void createRegisterGroups() {
 		fRegisterGroups = Collections.synchronizedList( new ArrayList( 20 ) );
 		ILaunchConfiguration config = getDebugTarget().getLaunch().getLaunchConfiguration();
@@ -209,7 +237,7 @@ public class CRegisterManager {
 		}
 	}
 
-	private void initializeDefaults() {
+	protected void initializeDefaults() {
 		String current = null;
 		int startIndex = 0;
 		for ( int i = 0; i < fRegisterDescriptors.length; ++i ) {
diff --git a/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/internal/core/model/CDebugTarget.java b/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/internal/core/model/CDebugTarget.java
index 23fa2c93704..c03eb8839d7 100644
--- a/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/internal/core/model/CDebugTarget.java
+++ b/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/internal/core/model/CDebugTarget.java
@@ -1755,6 +1755,13 @@ public class CDebugTarget extends CDebugElement implements ICDebugTarget, ICDIEv
 		getRegisterManager().modifyRegisterGroup( group, descriptors );
 	}
 
+	/* (non-Javadoc)
+	 * @see org.eclipse.cdt.debug.core.model.ICDebugTarget#restoreDefaultRegisterGroups()
+	 */
+	public void restoreDefaultRegisterGroups() {
+		getRegisterManager().restoreDefaults();
+	}
+
 	protected void skipBreakpoints( boolean enabled ) {
 		getBreakpointManager().skipBreakpoints( enabled );
 	}
diff --git a/debug/org.eclipse.cdt.debug.ui/ChangeLog b/debug/org.eclipse.cdt.debug.ui/ChangeLog
index dab1cdcdd9d..7b60097802c 100644
--- a/debug/org.eclipse.cdt.debug.ui/ChangeLog
+++ b/debug/org.eclipse.cdt.debug.ui/ChangeLog
@@ -1,3 +1,10 @@
+2005-06-09 Mikhail Khodjaiants
+	Bug 94139: User-defined register groups.
+	Support fo the "Restore Default Register Groups" action.
+	+ RestoreDefaultRegisterGroupsActionDelegate.java
+	* plugin.properties
+	* plugin.xml
+
 2005-06-07 Mikhail Khodjaiants
 	New images for mapping source containers.
 	* icons/obj16/mapentry_obj.gif
diff --git a/debug/org.eclipse.cdt.debug.ui/plugin.properties b/debug/org.eclipse.cdt.debug.ui/plugin.properties
index 05d6f5809f8..33706161a29 100644
--- a/debug/org.eclipse.cdt.debug.ui/plugin.properties
+++ b/debug/org.eclipse.cdt.debug.ui/plugin.properties
@@ -126,3 +126,5 @@ RemoveRegisterGroupAction.label=Remove Register Group
 RemoveRegisterGroupAction.tooltip=Remove Register Group
 EditRegisterGroupAction.label=Edit Register Group
 EditRegisterGroupAction.tooltip=Edit Register Group
+RestoredefaultRegisterGroupsAction.label=Restore Default Register Groups
+RestoredefaultRegisterGroupsAction.tooltip=Restore Default Register Groups
diff --git a/debug/org.eclipse.cdt.debug.ui/plugin.xml b/debug/org.eclipse.cdt.debug.ui/plugin.xml
index a18e4326b43..51c067ca944 100644
--- a/debug/org.eclipse.cdt.debug.ui/plugin.xml
+++ b/debug/org.eclipse.cdt.debug.ui/plugin.xml
@@ -650,6 +650,20 @@
                   class="org.eclipse.cdt.debug.core.model.ICVariable">
             </selection>
          </action>
+         <action
+               class="org.eclipse.cdt.debug.internal.ui.actions.RestoreDefaultRegisterGroupsActionDelegate"
+               helpContextId="restore_default_register_groups_action_context"
+               id="org.eclipse.cdt.debug.ui.restoreDefaultRegisterGroupsAction"
+               label="%RestoredefaultRegisterGroupsAction.label"
+               menubarPath="additions"
+               style="push"
+               tooltip="%RestoredefaultRegisterGroupsAction.tooltip">
+            <enablement>
+               <pluginState
+                     id="org.eclipse.cdt.debug.ui.pluginState1"
+                     value="activated"/>
+            </enablement>
+         </action>
          <action
                class="org.eclipse.cdt.debug.internal.ui.actions.AddRegisterGroupActionDelegate"
                helpContextId="add_register_group_action_context"
diff --git a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/RestoreDefaultRegisterGroupsActionDelegate.java b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/RestoreDefaultRegisterGroupsActionDelegate.java
new file mode 100644
index 00000000000..2e60ff226e8
--- /dev/null
+++ b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/RestoreDefaultRegisterGroupsActionDelegate.java
@@ -0,0 +1,64 @@
+/**********************************************************************
+ * Copyright (c) 2004 QNX Software Systems and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Common Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/cpl-v10.html
+ *
+ * Contributors:
+ * QNX Software Systems - Initial API and implementation
+ ***********************************************************************/ 
+package org.eclipse.cdt.debug.internal.ui.actions; 
+
+import org.eclipse.cdt.debug.core.model.ICDebugTarget;
+import org.eclipse.debug.core.DebugEvent;
+import org.eclipse.debug.core.DebugException;
+import org.eclipse.debug.core.model.IDebugElement;
+import org.eclipse.debug.ui.DebugUITools;
+import org.eclipse.jface.action.IAction;
+import org.eclipse.jface.viewers.StructuredSelection;
+ 
+
+public class RestoreDefaultRegisterGroupsActionDelegate extends AbstractViewActionDelegate {
+
+	protected String getErrorDialogTitle() {
+		return "Error";
+	}
+
+	protected String getErrorDialogMessage() {
+		return "Error(s) occurred restoring default register groups.";
+	}
+
+	protected void doAction() throws DebugException {
+		getDebugTarget().restoreDefaultRegisterGroups();
+	}
+
+	protected void update() {
+		IAction action = getAction();
+		if ( action != null ) {
+			ICDebugTarget target = getDebugTarget();
+			action.setEnabled( ( target != null ) ? target.isSuspended() : false );
+		}
+	}
+
+	protected void doHandleDebugEvent( DebugEvent event ) {
+	}
+
+	private ICDebugTarget getDebugTarget() {
+		Object element = getSelection().getFirstElement();
+		if ( element instanceof IDebugElement ) {
+			return (ICDebugTarget)((IDebugElement)element).getDebugTarget().getAdapter( ICDebugTarget.class );
+		}
+		return null;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.cdt.debug.internal.ui.actions.AbstractViewActionDelegate#init(org.eclipse.jface.action.IAction)
+	 */
+	public void init( IAction action ) {
+		super.init( action );
+		Object element = DebugUITools.getDebugContext();
+		setSelection( (element != null) ? new StructuredSelection( element ) : new StructuredSelection() );
+		update();
+	}
+}