--- a/src/viewer_swing/java/com/glavsoft/viewer/Viewer.java	Fri Jun 17 17:06:22 2016 +0900
+++ b/src/viewer_swing/java/com/glavsoft/viewer/Viewer.java	Sat Jun 18 20:09:46 2016 +0900
@@ -28,10 +28,13 @@
 import com.glavsoft.transport.Reader;
 import com.glavsoft.transport.Writer;
 import com.glavsoft.viewer.cli.Parser;
-import com.glavsoft.viewer.swing.*;
+import com.glavsoft.viewer.swing.ConnectionParams;
+import com.glavsoft.viewer.swing.ParametersHandler;
+import com.glavsoft.viewer.swing.SwingViewerWindow;
+import jp.ac.u_ryukyu.treevnc.CreateConnectionParam;
+import jp.ac.u_ryukyu.treevnc.TreeRFBProto;
 
 import javax.swing.*;
-
 import java.awt.*;
 import java.awt.event.WindowEvent;
 import java.awt.event.WindowListener;
@@ -41,10 +44,10 @@
 import java.util.ArrayList;
 import java.util.jar.Attributes;
 import java.util.jar.Manifest;
-import java.util.logging.*;
-
-import jp.ac.u_ryukyu.treevnc.CreateConnectionParam;
-import jp.ac.u_ryukyu.treevnc.TreeRFBProto;
+import java.util.logging.ConsoleHandler;
+import java.util.logging.Handler;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 @SuppressWarnings("serial")
 public class Viewer extends JApplet implements Runnable, WindowListener , ViewerInterface {
@@ -417,7 +420,6 @@
             myRfb.fixingSizeWidth = fixingSizeWidth;
             myRfb.fixingSizeHeight = fixingSizeHeight;
         }
-        myRfb.setFilterSingleDisplay(filterSingleDisplay);
         myRfb.setCuiVersion(false);
         myRfb.setHasViewer(true); // this flag will be overwrited after this method. Do we have to set here?
         if (myRfb.getAcceptThread() == null) {
@@ -498,12 +500,25 @@
 
         for (GraphicsDevice gd : gs) {
             for (GraphicsConfiguration r : gd.getConfigurations()) {
-                rectangles.add(r.getBounds());
+                Rectangle rect = r.getBounds();
+                rectangles.add(rect);
             }
         }
         return rectangles;
     }
 
+    public Point getScreenOffset(ArrayList<Rectangle> rectangles) {
+        // position of screen may negavie, but RFBscreen position is always positive
+        // compute offset to make them positive
+        int offsetx = 0;
+        int offsety = 0;
+        for (Rectangle rect : rectangles) {
+            if (rect.x < offsetx) offsetx = rect.x;
+            if (rect.y < offsety) offsety = rect.y;
+        }
+        return new Point(-offsetx,-offsety);
+    }
+
 
     @Override
     public void setFitScreen() {