Index: trunk/src/org/openstreetmap/josm/actions/AddImageryLayerAction.java
===================================================================
--- trunk/src/org/openstreetmap/josm/actions/AddImageryLayerAction.java	(revision 5090)
+++ trunk/src/org/openstreetmap/josm/actions/AddImageryLayerAction.java	(revision 5091)
@@ -11,4 +11,5 @@
 import org.openstreetmap.josm.data.imagery.ImageryInfo;
 import org.openstreetmap.josm.data.imagery.ImageryInfo.ImageryType;
+import org.openstreetmap.josm.gui.actionsupport.AlignImageryPanel;
 import org.openstreetmap.josm.gui.layer.ImageryLayer;
 import org.openstreetmap.josm.tools.ImageProvider;
@@ -44,4 +45,5 @@
         try {
             Main.main.addLayer(ImageryLayer.create(info));
+            AlignImageryPanel.addNagPanelIfNeeded();
         } catch (IllegalArgumentException ex) {
             if (ex.getMessage() == null || ex.getMessage().isEmpty()) {
Index: trunk/src/org/openstreetmap/josm/gui/MapFrame.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/MapFrame.java	(revision 5090)
+++ trunk/src/org/openstreetmap/josm/gui/MapFrame.java	(revision 5091)
@@ -5,7 +5,9 @@
 
 import java.awt.BorderLayout;
+import java.awt.Component;
 import java.awt.Container;
 import java.awt.Dimension;
 import java.awt.Font;
+import java.awt.GridBagLayout;
 import java.awt.Rectangle;
 import java.awt.event.ActionEvent;
@@ -65,4 +67,5 @@
 import org.openstreetmap.josm.gui.widgets.PopupMenuLauncher;
 import org.openstreetmap.josm.tools.Destroyable;
+import org.openstreetmap.josm.tools.GBC;
 
 /**
@@ -113,4 +116,5 @@
      */
     private List<ToggleDialog> allDialogs = new ArrayList<ToggleDialog>();
+    private final JPanel leftPanel;
     private final DialogsPanel dialogsPanel;
 
@@ -140,8 +144,14 @@
         setLayout(new BorderLayout());
 
+        
         mapView = new MapView(contentPane);
 
         new FileDrop(mapView);
-
+        
+        leftPanel = new JPanel(); 
+        leftPanel.setLayout(new GridBagLayout());
+        
+        leftPanel.add(mapView, GBC.std().fill()); 
+ 	
         // toolbar
         toolBarActions.setFloatable(false);
@@ -158,5 +168,5 @@
         JSplitPane splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, true);
         dialogsPanel = new DialogsPanel(splitPane);
-        splitPane.setLeftComponent(mapView);
+        splitPane.setLeftComponent(leftPanel);
         splitPane.setRightComponent(dialogsPanel);
 
@@ -499,4 +509,43 @@
         Main.pref.putInteger("toggleDialogs.width", dialogsPanel.getWidth());
     }
+    
+     /*
+     * Remove panel from top of MapView by class
+     */
+     public void removeTopPanel(Class<?> type) {
+        int n = leftPanel.getComponentCount();
+        for (int i=0; i<n; i++) {
+            Component c = leftPanel.getComponent(i);
+            if (type.isInstance(c)) {
+                leftPanel.remove(i);
+                leftPanel.doLayout();
+//                repaint();
+                return;
+            }
+        }
+    }
+    
+    /*
+    * Find panel on top of MapView by class
+    */
+    public <T> T getTopPanel(Class<T> type) {
+        int n = leftPanel.getComponentCount();
+        for (int i=0; i<n; i++) {
+            Component c = leftPanel.getComponent(i);
+            if (type.isInstance(c)) {
+                return type.cast(c);
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Add component @param c on top of MapView
+     */
+    public void addTopPanel(Component c) {
+        leftPanel.add(c, GBC.eol().fill(GBC.HORIZONTAL), leftPanel.getComponentCount()-1);
+        leftPanel.doLayout();
+        c.doLayout();
+    }
 
     /**
Index: trunk/src/org/openstreetmap/josm/gui/actionsupport/AlignImageryPanel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/actionsupport/AlignImageryPanel.java	(revision 5091)
+++ trunk/src/org/openstreetmap/josm/gui/actionsupport/AlignImageryPanel.java	(revision 5091)
@@ -0,0 +1,81 @@
+package org.openstreetmap.josm.gui.actionsupport;
+
+
+import java.awt.BorderLayout;
+import java.awt.Color;
+import java.awt.Font;
+import java.awt.Graphics;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+import java.awt.event.MouseEvent;
+import java.awt.event.MouseListener;
+import javax.swing.BoxLayout;
+import javax.swing.JButton;
+import javax.swing.JLabel;
+import javax.swing.JPanel;
+import javax.swing.Box;
+import javax.swing.JSplitPane;
+import javax.swing.border.CompoundBorder;
+import javax.swing.border.EmptyBorder;
+import javax.swing.border.EtchedBorder;
+
+import org.openstreetmap.josm.Main;
+import static org.openstreetmap.josm.tools.I18n.tr;
+import org.openstreetmap.josm.tools.ImageProvider;
+import org.openstreetmap.josm.tools.UrlLabel;
+
+
+/**
+ * The panel to nag a user ONCE that he/she has to align imagery.
+ * 
+ * @author zverik
+ */
+public class AlignImageryPanel extends JPanel {
+    private static final String PREF = "imagery.offsetnagging";
+
+    public AlignImageryPanel() {
+        super();
+        
+        Font font = getFont().deriveFont(Font.PLAIN, 14.0f);
+        JLabel nagLabel = new JLabel(tr("Aerial imagery might be misaligned. Please check its offset using GPS tracks!"));
+        UrlLabel detailsList = new UrlLabel(tr("http://wiki.openstreetmap.org/wiki/Using_Imagery"), tr("Details..."));
+        nagLabel.setFont(font);
+        detailsList.setFont(font);
+        
+        JButton closeButton = new JButton(ImageProvider.get("misc", "black_x"));
+        closeButton.setContentAreaFilled(false);
+        closeButton.setRolloverEnabled(true);
+        closeButton.setBorderPainted(false);
+        closeButton.setToolTipText(tr("Hide this message and never show it again"));
+        closeButton.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed( ActionEvent e ) {
+                if (Main.map!=null) {
+                    Main.map.removeTopPanel(AlignImageryPanel.class);
+                    Main.pref.put(PREF, false);
+                }
+            }
+        });
+        
+        BoxLayout box = new BoxLayout(this, BoxLayout.X_AXIS);
+        setLayout(box);
+        add(nagLabel);
+        add(Box.createHorizontalStrut(12));
+        add(detailsList);
+        add(Box.createHorizontalGlue());
+        add(closeButton);
+//        setBorder(new EmptyBorder(12, 12, 12, 12));
+        setBorder(new CompoundBorder(new EtchedBorder(EtchedBorder.LOWERED), new EmptyBorder(12, 12, 12, 12)));
+        setBackground(new Color(224, 236, 249));
+    }
+
+    public static void addNagPanelIfNeeded() {
+        if( Main.map != null && !Main.pref.getBoolean("expert") && Main.pref.getBoolean(PREF, true) ) {
+            if (Main.map.getTopPanel(AlignImageryPanel.class) == null) {
+                AlignImageryPanel p = new AlignImageryPanel();
+                Main.map.addTopPanel(p);
+            }
+        }
+    }
+    
+}