diff --git a/vncviewer/cocoa.mm b/vncviewer/cocoa.mm
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+++ b/vncviewer/cocoa.mm
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+/* Copyright 2011 Pierre Ossman <ossman@cendio.se> for Cendio AB
+ * 
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+
+#include <FL/Fl.H>
+#include <FL/Fl_Window.H>
+#include <FL/x.H>
+
+#import <Cocoa/Cocoa.h>
+
+int cocoa_capture_display(Fl_Window *win)
+{
+  NSWindow *nsw;
+
+  nsw = (NSWindow*)fl_xid(win);
+
+  // Already captured?
+  if ([nsw level] == CGShieldingWindowLevel())
+    return 0;
+
+  if (CGDisplayCapture(kCGDirectMainDisplay) != kCGErrorSuccess)
+    return 1;
+
+  [nsw setLevel:CGShieldingWindowLevel()];
+
+  return 0;
+}
+
+void cocoa_release_display(Fl_Window *win)
+{
+  NSWindow *nsw;
+  int newlevel;
+
+  CGDisplayRelease(kCGDirectMainDisplay);
+
+  nsw = (NSWindow*)fl_xid(win);
+
+  // Someone else has already changed the level of this window
+  if ([nsw level] != CGShieldingWindowLevel())
+    return;
+
+  // FIXME: Store the previous level somewhere so we don't have to hard
+  //        code a level here.
+#ifdef HAVE_FLTK_FULLSCREEN
+  if (win->fullscreen_active() && win->contains(Fl::focus()))
+    newlevel = NSStatusWindowLevel;
+  else
+#endif
+    newlevel = NSNormalWindowLevel;
+
+  // Only change if different as the level change also moves the window
+  // to the top of that level.
+  if ([nsw level] != newlevel)
+    [nsw setLevel:newlevel];
+}