Index: core/src/org/openstreetmap/josm/gui/ExtendedDialog.java
===================================================================
--- core/src/org/openstreetmap/josm/gui/ExtendedDialog.java	(revision 4475)
+++ core/src/org/openstreetmap/josm/gui/ExtendedDialog.java	(working copy)
@@ -455,7 +455,7 @@
         if(rememberSizePref.length() != 0 && defaultWindowGeometry != null) {
             if(visible) {
                 new WindowGeometry(rememberSizePref,
-                        defaultWindowGeometry).applySafe(this);
+                        defaultWindowGeometry).applySafeMultiScreen(this);
             } else {
                 new WindowGeometry(this).remember(rememberSizePref);
             }
Index: core/src/org/openstreetmap/josm/tools/WindowGeometry.java
===================================================================
--- core/src/org/openstreetmap/josm/tools/WindowGeometry.java	(revision 4475)
+++ core/src/org/openstreetmap/josm/tools/WindowGeometry.java	(working copy)
@@ -5,7 +5,11 @@
 
 import java.awt.Component;
 import java.awt.Dimension;
+import java.awt.GraphicsConfiguration;
+import java.awt.GraphicsDevice;
+import java.awt.GraphicsEnvironment;
 import java.awt.Point;
+import java.awt.Rectangle;
 import java.awt.Toolkit;
 import java.awt.Window;
 import java.util.regex.Matcher;
@@ -101,7 +105,7 @@
     protected int parseField(String preferenceKey, String preferenceValue, String field) throws WindowGeometryException {
         String v = "";
         try {
-            Pattern p = Pattern.compile(field + "=(\\d+)",Pattern.CASE_INSENSITIVE);
+            Pattern p = Pattern.compile(field + "=(-?\\d+)",Pattern.CASE_INSENSITIVE);
             Matcher m = p.matcher(preferenceValue);
             if (!m.find())
                 throw new WindowGeometryException(tr("Preference with key ''{0}'' does not include ''{1}''. Cannot restore window geometry from preferences.", preferenceKey, field));
@@ -213,13 +217,49 @@
      */
     public void applySafe(Window window) {
         Point p = new Point(topLeft);
-        if (p.x > Toolkit.getDefaultToolkit().getScreenSize().width - 10) {
-            p.x  = 0;
+        if (p.x < 0 || p.x > Toolkit.getDefaultToolkit().getScreenSize().width - 10) {
+            p.x = 0;
         }
-        if (p.y >  Toolkit.getDefaultToolkit().getScreenSize().height - 10) {
+        if (p.y < 0 || p.y > Toolkit.getDefaultToolkit().getScreenSize().height - 10) {
             p.y = 0;
         }
         window.setLocation(p);
         window.setSize(extent);
     }
+    
+    /**
+     * Applies this geometry to a window. Makes sure that the window is not placed outside
+     * of the coordinate range of all available screens.
+     *
+     * @param window the window
+     */
+    public void applySafeMultiScreen(Window window) {
+        Point p = new Point(topLeft);
+        
+		Rectangle virtualBounds = new Rectangle();
+		GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
+		GraphicsDevice[] gs = ge.getScreenDevices();
+		for (int j = 0; j < gs.length; j++) {
+			GraphicsDevice gd = gs[j];
+			GraphicsConfiguration[] gc = gd.getConfigurations();
+			for (int i = 0; i < gc.length; i++) {
+				virtualBounds = virtualBounds.union(gc[i].getBounds());
+			}
+		}
+		
+        if (p.x < virtualBounds.x) {
+            p.x = virtualBounds.x;
+        } else if (p.x > virtualBounds.x + virtualBounds.width - extent.width) {
+        	p.x = virtualBounds.x + virtualBounds.width - extent.width;
+        }
+		
+        if (p.y < virtualBounds.y) {
+            p.y = virtualBounds.y;
+        } else if (p.y > virtualBounds.y + virtualBounds.height - extent.height) {
+        	p.y = virtualBounds.y + virtualBounds.height - extent.height;
+        }
+        
+        window.setLocation(p);
+        window.setSize(extent);
+    }
 }