diff --git a/debug/org.eclipse.cdt.debug.ui/ChangeLog b/debug/org.eclipse.cdt.debug.ui/ChangeLog
index ca6a28f07a2..3b4330f49ed 100644
--- a/debug/org.eclipse.cdt.debug.ui/ChangeLog
+++ b/debug/org.eclipse.cdt.debug.ui/ChangeLog
@@ -1,3 +1,9 @@
+2003-04-08 Mikhail Khodjaiants
+	Preserving the registers tree structure during the debug session.
+	* ViewerState.java: new
+	* RegistersView.java
+	* RegistersViewEventHandler.java
+	
 2003-04-07 Mikhail Khodjaiants
 	No dialog if switch to frame failed.
 	* CDebugUIPlugin.java
diff --git a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/ViewerState.java b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/ViewerState.java
new file mode 100644
index 00000000000..168bc3af53d
--- /dev/null
+++ b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/ViewerState.java
@@ -0,0 +1,60 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2003 IBM Corporation 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:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+
+package org.eclipse.cdt.debug.internal.ui.views;
+
+import org.eclipse.jface.viewers.ISelection;
+import org.eclipse.jface.viewers.TreeViewer;
+
+/**
+ * Memento of the expanded and selected items in a tree
+ * viewer for.
+ * 
+ * @since 2.1
+ */
+public class ViewerState {
+
+	private Object[] fExpandedElements = null;	
+	private ISelection fSelection = null;
+	
+	/**
+	 * Constructs a memento for the given viewer.
+	 */
+	public ViewerState(TreeViewer viewer) {
+		saveState(viewer);
+	}
+
+	/**
+	 * Saves the current state of the given viewer into
+	 * this memento.
+	 * 
+	 * @param viewer viewer of which to save the state
+	 */
+	public void saveState(TreeViewer viewer) {
+		fExpandedElements = viewer.getExpandedElements();
+		fSelection = viewer.getSelection();
+	}
+	
+	/**
+	 * Restores the state of the given viewer to this mementos
+	 * saved state.
+	 * 
+	 * @param viewer viewer to which state is restored
+	 */
+	public void restoreState(TreeViewer viewer) {
+		if (fExpandedElements != null) {
+			viewer.setExpandedElements(fExpandedElements);
+		}
+		if (fSelection != null) {
+			viewer.setSelection(fSelection);
+		}
+	}
+}
diff --git a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/registers/RegistersView.java b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/registers/RegistersView.java
index f1bed652eaa..c93a2f43fee 100644
--- a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/registers/RegistersView.java
+++ b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/registers/RegistersView.java
@@ -6,6 +6,8 @@
 
 package org.eclipse.cdt.debug.internal.ui.views.registers;
 
+import java.util.HashMap;
+
 import org.eclipse.cdt.debug.core.ICRegisterManager;
 import org.eclipse.cdt.debug.internal.ui.CDebugImages;
 import org.eclipse.cdt.debug.internal.ui.ICDebugHelpContextIds;
@@ -17,6 +19,7 @@ import org.eclipse.cdt.debug.internal.ui.preferences.ICDebugPreferenceConstants;
 import org.eclipse.cdt.debug.internal.ui.views.AbstractDebugEventHandler;
 import org.eclipse.cdt.debug.internal.ui.views.AbstractDebugEventHandlerView;
 import org.eclipse.cdt.debug.internal.ui.views.IDebugExceptionHandler;
+import org.eclipse.cdt.debug.internal.ui.views.ViewerState;
 import org.eclipse.cdt.debug.ui.CDebugUIPlugin;
 import org.eclipse.cdt.debug.ui.ICDebugUIConstants;
 import org.eclipse.debug.core.DebugException;
@@ -60,6 +63,14 @@ public class RegistersView extends AbstractDebugEventHandlerView
 
 	protected static final String VARIABLES_SELECT_ALL_ACTION = SELECT_ALL_ACTION + ".Registers"; //$NON-NLS-1$
 
+	/**
+	 * A map of register managers to <code>ViewerState</code>s.
+	 * Used to restore the expanded state of the registers view on
+	 * re-selection of the register manager. The cache is cleared on
+	 * a frame by frame basis when a thread/target is terminated.
+	 */
+	private HashMap fExpandedRegisters = new HashMap( 10 );
+
 	/* (non-Javadoc)
 	 * @see org.eclipse.debug.ui.AbstractDebugView#createViewer(Composite)
 	 */
@@ -262,8 +273,26 @@ public class RegistersView extends AbstractDebugEventHandlerView
 			return;
 		}
 
+		if ( current != null )
+		{
+			// save state
+			ViewerState state = new ViewerState( getRegistersViewer() );
+			fExpandedRegisters.put( current, state );
+		}
+
 		showViewer();
 		getViewer().setInput( rm );
+
+		// restore state
+		if ( rm != null ) 
+		{
+			ViewerState state = (ViewerState)fExpandedRegisters.get( rm );
+			if ( state != null ) 
+			{
+				state.restoreState( getRegistersViewer() );
+			}
+		}
+
 		updateObjects();
 	}
 
@@ -279,4 +308,14 @@ public class RegistersView extends AbstractDebugEventHandlerView
 			setViewerInput( (IStructuredSelection)selection );
 		}
 	}
+	
+	protected RegistersViewer getRegistersViewer()
+	{
+		return (RegistersViewer)getViewer();
+	}
+
+	protected void clearExpandedRegisters( ICRegisterManager rm ) 
+	{
+		fExpandedRegisters.remove( rm );
+	}
 }
diff --git a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/registers/RegistersViewEventHandler.java b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/registers/RegistersViewEventHandler.java
index f573da16be9..75d33cc5ece 100644
--- a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/registers/RegistersViewEventHandler.java
+++ b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/registers/RegistersViewEventHandler.java
@@ -5,8 +5,10 @@
  */
 package org.eclipse.cdt.debug.internal.ui.views.registers;
 
+import org.eclipse.cdt.debug.core.ICRegisterManager;
 import org.eclipse.cdt.debug.internal.ui.views.AbstractDebugEventHandler;
 import org.eclipse.debug.core.DebugEvent;
+import org.eclipse.debug.core.model.IDebugTarget;
 import org.eclipse.debug.core.model.IVariable;
 import org.eclipse.debug.ui.AbstractDebugView;
 
@@ -38,6 +40,13 @@ public class RegistersViewEventHandler extends AbstractDebugEventHandler
 			DebugEvent event = events[i];
 			switch( event.getKind() )
 			{
+				case DebugEvent.TERMINATE :
+					if ( event.getSource() instanceof IDebugTarget &&
+						 ((IDebugTarget)event.getSource()).getAdapter( ICRegisterManager.class ) != null )
+					{
+						getRegistersView().clearExpandedRegisters( (ICRegisterManager)(((IDebugTarget)event.getSource()).getAdapter( ICRegisterManager.class )) );
+					}
+					break;
 				case DebugEvent.SUSPEND :
 					if ( event.getDetail() != DebugEvent.EVALUATION_IMPLICIT )
 					{
@@ -64,6 +73,11 @@ public class RegistersViewEventHandler extends AbstractDebugEventHandler
 					}
 					break;
 			}
-		}
+		}		
+	}
+
+	protected RegistersView getRegistersView()
+	{
+		return (RegistersView)getView();
 	}
 }