--- a/src/viewer_swing/java/com/glavsoft/viewer/TreeViewer.java	Mon May 26 19:47:09 2014 +0900
+++ b/src/viewer_swing/java/com/glavsoft/viewer/TreeViewer.java	Mon May 26 20:03:16 2014 +0900
@@ -10,6 +10,7 @@
 	private int height;
 	private String hostName = null;
 	private boolean noConnection = false;
+    private boolean permitChangeScreen = true;
 
 	public static void main(String[] args) {
 		new TreeViewer().vncStart(args);
@@ -21,6 +22,7 @@
 	        VncProxyService vps = new VncProxyService();
 	        vps.setNoConnection(noConnection);
 	        vps.proxyStart(args,width,height);
+	        if (!permitChangeScreen ) vps.getRfb().setPermitChangeScreen(false);
 	    }
 	    ViewerImpl v;
 	    if (viewer) {
@@ -57,7 +59,11 @@
 			} else if ("--version".equals(args[i])) {
 				System.out.println("version :" + VncProxyService.ver());
 				System.exit(0);
-			} else if ("--retina".equals(args[i])) {
+            } else if ("-ns".equals(args[i])) {
+                permitChangeScreen = false;
+            } else if ("--noScreenChange".equals(args[i])) {
+                permitChangeScreen = false;
+            } else if ("--retina".equals(args[i])) {
 				// retina display too large for TreeVNC.
 				// restrict display size.
 				width = 1280;
@@ -73,7 +79,8 @@
 			} else {
 				System.out.println("(default) TreeVNCClient\n"
 						+ "-v or -c:         View shared screen.\n"
-						+ "-p:               Share my screen and behave as tree root.\n"
+						+ "-p:               (proxy) Share my screen and behave as tree root.\n"
+                        + "-ns --noScreenChange     Viewers cannot change screen to thiers (default permite screen change)"  
 						+ "-d:               Show shared screen and behave as tree root.\n"
 						+ "-r:               Connect to fix to specified host and port.\n"
 						+ "--host hostname:  Set host name.\n"