diff -ur fltk-1.3.0r9619.org/configh.in fltk-1.3.0r9619/configh.in

--- fltk-1.3.0r9619.org/configh.in	2011-10-04 11:21:47.000000000 +0200

+++ fltk-1.3.0r9619/configh.in	2012-06-18 16:14:05.012277003 +0200

@@ -108,6 +108,14 @@

 #define USE_XDBE HAVE_XDBE

 /*

+ * HAVE_XFIXES:

+ *

+ * Do we have the X fixes extension?

+ */

+

+#define HAVE_XFIXES 0

+

+/*

  * __APPLE_QUARTZ__:

  *

  * All Apple implementations are now based on Quartz and Cocoa,

diff -ur fltk-1.3.0r9619.org/configure.in fltk-1.3.0r9619/configure.in

--- fltk-1.3.0r9619.org/configure.in	2012-06-18 16:13:38.744017220 +0200

+++ fltk-1.3.0r9619/configure.in	2012-06-18 16:14:05.013277050 +0200

@@ -999,6 +999,16 @@

 		LIBS="-lXext $LIBS")

 	fi

+	dnl Check for the Xfixes extension unless disabled...

+        AC_ARG_ENABLE(xfixes, [  --enable-xfixes       turn on Xfixes support [default=yes]])

+

+	if test x$enable_xfixes != xno; then

+	    AC_CHECK_HEADER(X11/extensions/Xfixes.h, AC_DEFINE(HAVE_XFIXES),,

+	        [#include <X11/Xlib.h>])

+	    AC_CHECK_LIB(Xfixes, XFixesQueryExtension,

+		LIBS="-lXfixes $LIBS")

+	fi

+

 	dnl Check for overlay visuals...

 	AC_PATH_PROG(XPROP, xprop)

 	AC_CACHE_CHECK(for X overlay visuals, ac_cv_have_overlay,

diff -ur fltk-1.3.0r9619.org/src/Fl_x.cxx fltk-1.3.0r9619/src/Fl_x.cxx

--- fltk-1.3.0r9619.org/src/Fl_x.cxx	2012-06-18 16:13:38.749017460 +0200

+++ fltk-1.3.0r9619/src/Fl_x.cxx	2012-06-18 16:13:24.000000000 +0200

@@ -53,6 +53,12 @@

 static int randrEventBase;                  // base of RandR-defined events

 #endif

+#  ifdef HAVE_XFIXES

+#  include <X11/extensions/Xfixes.h>

+static int xfixes_event_base = 0;

+static bool have_xfixes = false;

+#  endif

+

 static Fl_Xlib_Graphics_Driver fl_xlib_driver;

 static Fl_Display_Device fl_xlib_display(&fl_xlib_driver);

 Fl_Display_Device *Fl_Display_Device::_display = &fl_xlib_display;// the platform display

@@ -197,6 +203,14 @@

     Fl::handle(FL_MOVE, fl_xmousewin);

   }

 #endif

+

+#ifdef HAVE_XFIXES

+  int error_base;

+  if (XFixesQueryExtension(fl_display, &xfixes_event_base, &error_base))

+    have_xfixes = true;

+  else

+    have_xfixes = false;

+#endif

 }

 // these pointers are set by the Fl::lock() function:

@@ -917,6 +931,10 @@

 static void poll_clipboard_owner(void) {

   Window xid;

+  // No polling needed with Xfixes

+  if (have_xfixes)

+    return;

+

   // No one is interested, so no point polling

   if (fl_clipboard_notify_empty())

     return;

@@ -955,10 +973,12 @@

   timestamp = clipboard ? &clipboard_timestamp : &primary_timestamp;

-  // Initial scan, just store the value

-  if (*timestamp == (Time)-1) {

-    *timestamp = time;

-    return;

+  if (!have_xfixes) {

+    // Initial scan, just store the value

+    if (*timestamp == (Time)-1) {

+      *timestamp = time;

+      return;

+    }

   }

   // Same selection

@@ -978,10 +998,12 @@

     primary_timestamp = -1;

     clipboard_timestamp = -1;

   } else {

-    poll_clipboard_owner();

+    if (!have_xfixes) {

+      poll_clipboard_owner();

-    if (!Fl::has_timeout(clipboard_timeout))

-      Fl::add_timeout(0.5, clipboard_timeout);

+      if (!Fl::has_timeout(clipboard_timeout))

+        Fl::add_timeout(0.5, clipboard_timeout);

+    }

   }

 }

@@ -1780,6 +1802,25 @@

     }

   }

+#ifdef HAVE_XFIXES

+  switch (xevent.type - xfixes_event_base) {

+  case XFixesSelectionNotify: {

+    // Someone feeding us bogus events?

+    if (!have_xfixes)

+      return true;

+

+    XFixesSelectionNotifyEvent *selection_notify = (XFixesSelectionNotifyEvent *)&xevent;

+

+    if ((selection_notify->selection == XA_PRIMARY) && !fl_i_own_selection[0])

+      handle_clipboard_timestamp(0, selection_notify->selection_timestamp);

+    else if ((selection_notify->selection == CLIPBOARD) && !fl_i_own_selection[1])

+      handle_clipboard_timestamp(1, selection_notify->selection_timestamp);

+

+    return true;

+    }

+  }

+#endif

+

   return Fl::handle(event, window);

 }

@@ -2100,6 +2141,16 @@

     XChangeProperty(fl_display, xp->xid, net_wm_type, XA_ATOM, 32, PropModeReplace, (unsigned char*)&net_wm_type_kind, 1);

   }

+#ifdef HAVE_XFIXES

+  // register for clipboard change notifications

+  if (have_xfixes && !win->parent()) {

+    XFixesSelectSelectionInput(fl_display, xp->xid, XA_PRIMARY,

+                               XFixesSetSelectionOwnerNotifyMask);

+    XFixesSelectSelectionInput(fl_display, xp->xid, CLIPBOARD,

+                               XFixesSetSelectionOwnerNotifyMask);

+  }

+#endif

+

   XMapWindow(fl_display, xp->xid);

   if (showit) {

     win->set_visible();