diff --git a/debug/org.eclipse.cdt.debug.core/ChangeLog b/debug/org.eclipse.cdt.debug.core/ChangeLog
index 2711a6b0057..42399995b3b 100644
--- a/debug/org.eclipse.cdt.debug.core/ChangeLog
+++ b/debug/org.eclipse.cdt.debug.core/ChangeLog
@@ -1,3 +1,12 @@
+2005-06-07 Mikhail Khodjaiants
+	Bug 94139: User-defined register groups.
+	Support fo the "Edit Register Group" action.
+	* ICDebugTarget.java
+	* IPersistableRegisterGroup.java
+	* CRegisterManager.java
+	* CDebugTarget.java
+	* CRegisterGroup.java
+
 2005-06-07 Mikhail Khodjaiants
 	The endianness flag is not chached.
 	* CDebugTarget.java
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 b72334dcaea..50c74ed150d 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
@@ -106,7 +106,7 @@ public interface ICDebugTarget extends IDebugTarget,
 	 * 
 	 * @since 3.0
 	 */
-	public void addUserDefinedRegisterGroup( String name, IRegisterDescriptor[]  descriptors );
+	public void addRegisterGroup( String name, IRegisterDescriptor[]  descriptors );
 
 	/**
 	 * Removes the given register group from the target
@@ -116,4 +116,14 @@ public interface ICDebugTarget extends IDebugTarget,
 	 * @since 3.0
 	 */
 	public void removeRegisterGroups( IRegisterGroup[] groups );
+
+	/**
+	 * Replace the given group's register descriptors by the specified descriptors.
+	 *  
+	 * @param group a group to be modified
+	 * @param descriptors a descriptor array to replace existing descriptors
+	 * 
+	 * @since 3.0
+	 */
+	public void modifyRegisterGroup( IPersistableRegisterGroup group, IRegisterDescriptor[] descriptors );
 }
diff --git a/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/core/model/IPersistableRegisterGroup.java b/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/core/model/IPersistableRegisterGroup.java
index 1b3f6f3d4ab..fd3ae2b19d4 100644
--- a/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/core/model/IPersistableRegisterGroup.java
+++ b/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/core/model/IPersistableRegisterGroup.java
@@ -36,4 +36,18 @@ public interface IPersistableRegisterGroup extends IRegisterGroup {
 	 * @exception CoreException on failure to initialize 
 	 */
 	public void initializeFromMemento( String memento ) throws CoreException;
+
+	/**
+	 * Returns the array of group's register descriptors.
+	 * 
+	 * @return the array of group's register descriptors
+	 */
+	public IRegisterDescriptor[] getRegisterDescriptors();
+
+	/**
+	 * Replaces the group register descriptors by the specified descriptors.
+	 *  
+	 * @param the array of register descriptors
+	 */
+	public void setRegisterDescriptors( IRegisterDescriptor[] registerDescriptors );
 }
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 1d8755fcd7d..4333a00b210 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
@@ -20,6 +20,7 @@ import org.eclipse.cdt.debug.core.ICDTLaunchConfigurationConstants;
 import org.eclipse.cdt.debug.core.cdi.CDIException;
 import org.eclipse.cdt.debug.core.cdi.model.ICDIRegisterDescriptor;
 import org.eclipse.cdt.debug.core.cdi.model.ICDIRegisterGroup;
+import org.eclipse.cdt.debug.core.model.IPersistableRegisterGroup;
 import org.eclipse.cdt.debug.core.model.IRegisterDescriptor;
 import org.eclipse.cdt.debug.internal.core.model.CDebugTarget;
 import org.eclipse.cdt.debug.internal.core.model.CRegisterDescriptor;
@@ -273,4 +274,15 @@ public class CRegisterManager {
 		}
 		return null;
 	}
+
+	public void modifyRegisterGroup( final IPersistableRegisterGroup group, final IRegisterDescriptor[] descriptors ) {
+		DebugPlugin.getDefault().asyncExec( 
+				new Runnable() {
+					public void run() {
+						group.setRegisterDescriptors( descriptors );					
+						((CRegisterGroup)group).fireChangeEvent( DebugEvent.CONTENT );
+					}
+				} );
+		
+	}
 }
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 55d42a72eab..23fa2c93704 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
@@ -72,6 +72,7 @@ import org.eclipse.cdt.debug.core.model.IDebuggerProcessSupport;
 import org.eclipse.cdt.debug.core.model.IDisassembly;
 import org.eclipse.cdt.debug.core.model.IExecFileInfo;
 import org.eclipse.cdt.debug.core.model.IGlobalVariableDescriptor;
+import org.eclipse.cdt.debug.core.model.IPersistableRegisterGroup;
 import org.eclipse.cdt.debug.core.model.IRegisterDescriptor;
 import org.eclipse.cdt.debug.core.sourcelookup.CDirectorySourceContainer;
 import org.eclipse.cdt.debug.core.sourcelookup.ICSourceLocator;
@@ -1736,7 +1737,7 @@ public class CDebugTarget extends CDebugElement implements ICDebugTarget, ICDIEv
 	/* (non-Javadoc)
 	 * @see org.eclipse.cdt.debug.core.model.ICDebugTarget#addUserDefinedRegisterGroup(java.lang.String, org.eclipse.cdt.debug.core.model.IRegisterDescriptor[])
 	 */
-	public void addUserDefinedRegisterGroup( String name, IRegisterDescriptor[] descriptors ) {
+	public void addRegisterGroup( String name, IRegisterDescriptor[] descriptors ) {
 		getRegisterManager().addRegisterGroup( name, descriptors );
 	}
 
@@ -1747,6 +1748,13 @@ public class CDebugTarget extends CDebugElement implements ICDebugTarget, ICDIEv
 		getRegisterManager().removeRegisterGroups( groups );
 	}
 
+	/* (non-Javadoc)
+	 * @see org.eclipse.cdt.debug.core.model.ICDebugTarget#modifyRegisterGroup(org.eclipse.cdt.debug.core.model.IPersistableRegisterGroup, org.eclipse.cdt.debug.core.model.IRegisterDescriptor[])
+	 */
+	public void modifyRegisterGroup( IPersistableRegisterGroup group, IRegisterDescriptor[] descriptors ) {
+		getRegisterManager().modifyRegisterGroup( group, descriptors );
+	}
+
 	protected void skipBreakpoints( boolean enabled ) {
 		getBreakpointManager().skipBreakpoints( enabled );
 	}
diff --git a/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/internal/core/model/CRegisterGroup.java b/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/internal/core/model/CRegisterGroup.java
index ae180a63838..9ab8e3aa798 100644
--- a/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/internal/core/model/CRegisterGroup.java
+++ b/debug/org.eclipse.cdt.debug.core/src/org/eclipse/cdt/debug/internal/core/model/CRegisterGroup.java
@@ -97,15 +97,7 @@ public class CRegisterGroup extends CDebugElement implements IPersistableRegiste
 
 	public void dispose() {
 		fDisposed = true;
-		if (fRegisters == null) {
-			return;
-		}
-		for ( int i = 0; i < fRegisters.length; ++i ) {
-			if ( fRegisters[i] != null ) {
-				((CRegister)fRegisters[i]).dispose();
-			}
-		}
-		fRegisters = null;
+		invalidate();
 	}
 
 	public void targetSuspended() {
@@ -216,7 +208,7 @@ public class CRegisterGroup extends CDebugElement implements IPersistableRegiste
 			childNode = childNode.getNextSibling();
 		}
 		setName( groupName );
-		setRegisterDescriptors( (IRegisterDescriptor[])list.toArray( new IRegisterDescriptor[list.size()] ) );
+		fRegisterDescriptors = (IRegisterDescriptor[])list.toArray( new IRegisterDescriptor[list.size()] );
 		setEnabled( enabled );
 	}
 
@@ -229,11 +221,34 @@ public class CRegisterGroup extends CDebugElement implements IPersistableRegiste
 		fName = name;
 	}
 
-	private void setRegisterDescriptors( IRegisterDescriptor[] registerDescriptors ) {
+	/* (non-Javadoc)
+	 * @see org.eclipse.cdt.debug.core.model.IPersistableRegisterGroup#setRegisterDescriptors(org.eclipse.cdt.debug.core.model.IRegisterDescriptor[])
+	 */
+	public void setRegisterDescriptors( IRegisterDescriptor[] registerDescriptors ) {
+		invalidate();
 		fRegisterDescriptors = registerDescriptors;
 	}
 
+	/* (non-Javadoc)
+	 * @see org.eclipse.cdt.debug.core.model.IPersistableRegisterGroup#getRegisterDescriptors()
+	 */
+	public IRegisterDescriptor[] getRegisterDescriptors() {
+		return fRegisterDescriptors;
+	}
+
 	private CRegisterManager getRegisterManager() {
 		return (CRegisterManager)getDebugTarget().getAdapter( CRegisterManager.class );
 	}
+
+	private void invalidate() {
+		if (fRegisters == null) {
+			return;
+		}
+		for ( int i = 0; i < fRegisters.length; ++i ) {
+			if ( fRegisters[i] != null ) {
+				((CRegister)fRegisters[i]).dispose();
+			}
+		}
+		fRegisters = null;
+	}
 }
\ No newline at end of file
diff --git a/debug/org.eclipse.cdt.debug.ui/ChangeLog b/debug/org.eclipse.cdt.debug.ui/ChangeLog
index 779ac96af9a..d69d0f73e0b 100644
--- a/debug/org.eclipse.cdt.debug.ui/ChangeLog
+++ b/debug/org.eclipse.cdt.debug.ui/ChangeLog
@@ -1,3 +1,13 @@
+2005-06-07 Mikhail Khodjaiants
+	Bug 94139: User-defined register groups.
+	Support fo the "Edit Register Group" action.
+	* AbstractViewActionDelegate.java
+	* ActionMessages.properties
+	* AddRegisterGroupActionDelegate.java
+	+ EditRegisterGroupActionDelegate.java
+	* plugin.properties
+	* plugin.xml
+
 2005-05-31 Mikhail Khodjaiants
 	Bug 84816: The modification of the signal properties should be done in the background.
 	* SignalPropertyPage.java
diff --git a/debug/org.eclipse.cdt.debug.ui/plugin.properties b/debug/org.eclipse.cdt.debug.ui/plugin.properties
index 7cd67138e74..05d6f5809f8 100644
--- a/debug/org.eclipse.cdt.debug.ui/plugin.properties
+++ b/debug/org.eclipse.cdt.debug.ui/plugin.properties
@@ -124,3 +124,5 @@ AddRegisterGroupAction.label=Add Register Group
 AddRegisterGroupAction.tooltip=Add Register Group
 RemoveRegisterGroupAction.label=Remove Register Group
 RemoveRegisterGroupAction.tooltip=Remove Register Group
+EditRegisterGroupAction.label=Edit Register Group
+EditRegisterGroupAction.tooltip=Edit Register Group
diff --git a/debug/org.eclipse.cdt.debug.ui/plugin.xml b/debug/org.eclipse.cdt.debug.ui/plugin.xml
index bd370d068a0..a18e4326b43 100644
--- a/debug/org.eclipse.cdt.debug.ui/plugin.xml
+++ b/debug/org.eclipse.cdt.debug.ui/plugin.xml
@@ -729,7 +729,7 @@
       <objectContribution
             adaptable="false"
             id="org.eclipse.cdt.debug.ui.RegisterGroupActions"
-            objectClass="org.eclipse.debug.core.model.IRegisterGroup">
+            objectClass="org.eclipse.cdt.debug.core.model.IPersistableRegisterGroup">
          <action
                class="org.eclipse.cdt.debug.internal.ui.actions.RemoveRegisterGroupActionDelegate"
                enablesFor="+"
@@ -738,6 +738,14 @@
                label="%RemoveRegisterGroupAction.label"
                menubarPath="additions"
                tooltip="%RemoveRegisterGroupAction.tooltip"/>
+         <action
+               class="org.eclipse.cdt.debug.internal.ui.actions.EditRegisterGroupActionDelegate"
+               enablesFor="1"
+               helpContextId="edit_register_group_action_context"
+               id="org.eclipse.cdt.debug.ui.editRegisterGroupAction"
+               label="%EditRegisterGroupAction.label"
+               menubarPath="additions"
+               tooltip="%EditRegisterGroupAction.tooltip"/>
       </objectContribution>
    </extension>
    <extension
diff --git a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/AbstractViewActionDelegate.java b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/AbstractViewActionDelegate.java
index 3131af3b7f5..6ddefa47b37 100644
--- a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/AbstractViewActionDelegate.java
+++ b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/AbstractViewActionDelegate.java
@@ -17,7 +17,6 @@ import org.eclipse.debug.core.DebugEvent;
 import org.eclipse.debug.core.DebugException;
 import org.eclipse.debug.core.DebugPlugin;
 import org.eclipse.debug.core.IDebugEventSetListener;
-import org.eclipse.debug.internal.ui.DebugUIPlugin;
 import org.eclipse.debug.ui.DebugUITools;
 import org.eclipse.debug.ui.IDebugUIConstants;
 import org.eclipse.debug.ui.IDebugView;
@@ -109,12 +108,12 @@ public abstract class AbstractViewActionDelegate extends ActionDelegate implemen
 			}
 		} );
 		if ( !ms.isOK() ) {
-			IWorkbenchWindow window = DebugUIPlugin.getActiveWorkbenchWindow();
+			IWorkbenchWindow window = CDebugUIPlugin.getActiveWorkbenchWindow();
 			if ( window != null ) {
-				DebugUIPlugin.errorDialog( window.getShell(), getErrorDialogTitle(), getErrorDialogMessage(), ms.getChildren()[0] ); //$NON-NLS-1$
+				CDebugUIPlugin.errorDialog( getErrorDialogMessage(), ms.getChildren()[0] ); //$NON-NLS-1$
 			}
 			else {
-				DebugUIPlugin.log( ms );
+				CDebugUIPlugin.log( ms );
 			}
 		}
 	}
diff --git a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/ActionMessages.properties b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/ActionMessages.properties
index de86cf0c872..e863f56ec38 100644
--- a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/ActionMessages.properties
+++ b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/ActionMessages.properties
@@ -114,3 +114,4 @@ ToggleDetailPaneAction.6=Hide the Detail Pane so that only the Main Tree View is
 ToggleDetailPaneAction.7=Hide the Detail Pane so that only the Main Tree View is Visible
 AddRegisterGroupActionDelegate.0=Error
 AddRegisterGroupActionDelegate.1=Error(s) occurred adding register group.
+EditRegisterGroupActionDelegate.0=Unable to edit register group.
diff --git a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/AddRegisterGroupActionDelegate.java b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/AddRegisterGroupActionDelegate.java
index 4c1922c1c04..4ca2a17262a 100644
--- a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/AddRegisterGroupActionDelegate.java
+++ b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/AddRegisterGroupActionDelegate.java
@@ -44,7 +44,7 @@ public class AddRegisterGroupActionDelegate extends AbstractViewActionDelegate {
 	protected void doAction() throws DebugException {
 		RegisterGroupDialog dialog = new RegisterGroupDialog( getView().getSite().getShell(), getDebugTarget().getRegisterDescriptors() );
 		if ( dialog.open() == Window.OK ) {
-			getDebugTarget().addUserDefinedRegisterGroup( dialog.getName(), dialog.getDescriptors() );
+			getDebugTarget().addRegisterGroup( dialog.getName(), dialog.getDescriptors() );
 		}
 	}
 
diff --git a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/EditRegisterGroupActionDelegate.java b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/EditRegisterGroupActionDelegate.java
new file mode 100644
index 00000000000..8b0f2967bdd
--- /dev/null
+++ b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/EditRegisterGroupActionDelegate.java
@@ -0,0 +1,79 @@
+/**********************************************************************
+ * 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.cdt.debug.core.model.IPersistableRegisterGroup;
+import org.eclipse.cdt.debug.core.model.IRegisterDescriptor;
+import org.eclipse.cdt.debug.internal.core.model.CDebugTarget;
+import org.eclipse.cdt.debug.ui.CDebugUIPlugin;
+import org.eclipse.debug.core.DebugException;
+import org.eclipse.debug.core.model.IDebugTarget;
+import org.eclipse.jface.action.IAction;
+import org.eclipse.jface.viewers.ISelection;
+import org.eclipse.jface.viewers.IStructuredSelection;
+import org.eclipse.jface.window.Window;
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.ui.IObjectActionDelegate;
+import org.eclipse.ui.IWorkbenchPart;
+import org.eclipse.ui.actions.ActionDelegate;
+ 
+
+public class EditRegisterGroupActionDelegate extends ActionDelegate implements IObjectActionDelegate {
+
+	private IPersistableRegisterGroup fSelection;
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.ui.IObjectActionDelegate#setActivePart(org.eclipse.jface.action.IAction, org.eclipse.ui.IWorkbenchPart)
+	 */
+	public void setActivePart( IAction action, IWorkbenchPart targetPart ) {
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.ui.actions.ActionDelegate#selectionChanged(org.eclipse.jface.action.IAction, org.eclipse.jface.viewers.ISelection)
+	 */
+	public void selectionChanged( IAction action, ISelection selection ) {
+		if ( selection instanceof IStructuredSelection ) {
+			IStructuredSelection ss = (IStructuredSelection)selection;
+			if ( !ss.isEmpty() ) {
+				Object s = ss.getFirstElement();
+				if ( s instanceof IPersistableRegisterGroup ) {
+					fSelection = (IPersistableRegisterGroup)s;
+				}
+			}
+		}
+	}
+
+	private IPersistableRegisterGroup getRegisterGroup() {
+		return fSelection;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.ui.actions.ActionDelegate#run(org.eclipse.jface.action.IAction)
+	 */
+	public void run( IAction action ) {
+		IPersistableRegisterGroup group = getRegisterGroup();
+		IRegisterDescriptor[] all;
+		try {
+			all = ((CDebugTarget)group.getDebugTarget()).getRegisterDescriptors();
+			RegisterGroupDialog dialog = new RegisterGroupDialog( Display.getCurrent().getActiveShell(), group.getName(), all, group.getRegisterDescriptors() );
+			if ( dialog.open() == Window.OK ) {
+				IDebugTarget target = group.getDebugTarget();
+				if ( target instanceof ICDebugTarget ) {
+					((ICDebugTarget)target).modifyRegisterGroup( group, dialog.getDescriptors() );
+				}
+			}
+		}
+		catch( DebugException e ) {
+			CDebugUIPlugin.errorDialog( ActionMessages.getString( "EditRegisterGroupActionDelegate.0" ), e.getStatus() ); //$NON-NLS-1$
+		}
+	}
+}