diff -up fltk-1.3.x-r8659/src/Fl_x.cxx.orig fltk-1.3.x-r8659/src/Fl_x.cxx

--- fltk-1.3.x-r8659/src/Fl_x.cxx.orig	2011-05-17 16:37:11.092011814 +0200

+++ fltk-1.3.x-r8659/src/Fl_x.cxx	2011-05-18 13:51:06.135475325 +0200

@@ -309,6 +309,9 @@ static Atom WM_PROTOCOLS;

 static Atom fl_MOTIF_WM_HINTS;

 static Atom TARGETS;

 static Atom CLIPBOARD;

+static Atom TIMESTAMP;

+static Atom PRIMARY_TIMESTAMP;

+static Atom CLIPBOARD_TIMESTAMP;

 Atom fl_XdndAware;

 Atom fl_XdndSelection;

 Atom fl_XdndEnter;

@@ -678,6 +681,9 @@ void fl_open_display(Display* d) {

   fl_MOTIF_WM_HINTS     = XInternAtom(d, "_MOTIF_WM_HINTS",     0);

   TARGETS               = XInternAtom(d, "TARGETS",             0);

   CLIPBOARD             = XInternAtom(d, "CLIPBOARD",           0);

+  TIMESTAMP             = XInternAtom(d, "TIMESTAMP",           0);

+  PRIMARY_TIMESTAMP     = XInternAtom(d, "PRIMARY_TIMESTAMP",   0);

+  CLIPBOARD_TIMESTAMP   = XInternAtom(d, "CLIPBOARD_TIMESTAMP", 0);

   fl_XdndAware          = XInternAtom(d, "XdndAware",           0);

   fl_XdndSelection      = XInternAtom(d, "XdndSelection",       0);

   fl_XdndEnter          = XInternAtom(d, "XdndEnter",           0);

@@ -861,6 +881,86 @@ void Fl::copy(const char *stuff, int len

 }

 ////////////////////////////////////////////////////////////////

+// Code for tracking clipboard changes:

+

+static Time primary_timestamp = -1;

+static Time clipboard_timestamp = -1;

+

+extern bool fl_clipboard_notify_empty(void);

+extern void fl_trigger_clipboard_notify(int source);

+

+static void poll_clipboard_owner(void) {

+  Window xid;

+

+  // No one is interested, so no point polling

+  if (fl_clipboard_notify_empty())

+    return;

+

+  // We need a window for this to work

+  if (!Fl::first_window())

+    return;

+  xid = fl_xid(Fl::first_window());

+  if (!xid)

+    return;

+

+  // Request an update of the selection time for both the primary and

+  // clipboard selections. Magic continues when we get a SelectionNotify.

+  if (!fl_i_own_selection[0])

+    XConvertSelection(fl_display, XA_PRIMARY, TIMESTAMP, PRIMARY_TIMESTAMP,

+                      xid, fl_event_time);

+  if (!fl_i_own_selection[1])

+    XConvertSelection(fl_display, CLIPBOARD, TIMESTAMP, CLIPBOARD_TIMESTAMP,

+                      xid, fl_event_time);

+}

+

+static void clipboard_timeout(void *data)

+{

+  // No one is interested, so stop polling

+  if (fl_clipboard_notify_empty())

+    return;

+

+  poll_clipboard_owner();

+

+  Fl::repeat_timeout(0.5, clipboard_timeout);

+}

+

+static void handle_clipboard_timestamp(int clipboard, Time time)

+{

+  Time *timestamp;

+

+  timestamp = clipboard ? &clipboard_timestamp : &primary_timestamp;

+

+  // Initial scan, just store the value

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

+    *timestamp = time;

+    return;

+  }

+

+  // Same selection

+  if (time == *timestamp)

+    return;

+

+  *timestamp = time;

+

+  // Something happened! Let's tell someone!

+  fl_trigger_clipboard_notify(clipboard);

+}

+

+void fl_clipboard_notify_change() {

+  // Reset the timestamps if we've going idle so that you don't

+  // get a bogus immediate trigger next time they're activated.

+  if (fl_clipboard_notify_empty()) {

+    primary_timestamp = -1;

+    clipboard_timestamp = -1;

+  } else {

+    poll_clipboard_owner();

+

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

+      Fl::add_timeout(0.5, clipboard_timeout);

+  }

+}

+

+////////////////////////////////////////////////////////////////

 const XEvent* fl_xevent; // the current x event

 ulong fl_event_time; // the last timestamp from an x event

@@ -976,7 +1102,6 @@ int fl_handle(const XEvent& thisevent)

     return 0;

   case SelectionNotify: {

-    if (!fl_selection_requestor) return 0;

     static unsigned char* buffer = 0;

     if (buffer) {XFree(buffer); buffer = 0;}

     long bytesread = 0;

@@ -992,6 +1117,19 @@ int fl_handle(const XEvent& thisevent)

                              bytesread/4, 65536, 1, 0,

                              &actual, &format, &count, &remaining,

                              &portion)) break; // quit on error

+

+      if ((fl_xevent->xselection.property == PRIMARY_TIMESTAMP) ||

+          (fl_xevent->xselection.property == CLIPBOARD_TIMESTAMP)) {

+        if (portion && format == 32 && count == 1) {

+          Time t = *(unsigned int*)portion;

+          if (fl_xevent->xselection.property == CLIPBOARD_TIMESTAMP)

+            handle_clipboard_timestamp(1, t);

+          else

+            handle_clipboard_timestamp(0, t);

+        }

+        return true;

+      }

+

       if (actual == TARGETS || actual == XA_ATOM) {

 	Atom type = XA_STRING;

 	for (unsigned i = 0; i

@@ -1029,6 +1167,9 @@ int fl_handle(const XEvent& thisevent)

       buffer[bytesread] = 0;

       convert_crlf(buffer, bytesread);

     }

+

+    if (!fl_selection_requestor) return 0;

+

     Fl::e_text = buffer ? (char*)buffer : (char *)"";

     Fl::e_length = bytesread;

     int old_event = Fl::e_number;

@@ -1049,6 +1190,7 @@ int fl_handle(const XEvent& thisevent)

   case SelectionClear: {

     int clipboard = fl_xevent->xselectionclear.selection == CLIPBOARD;

     fl_i_own_selection[clipboard] = 0;

+    poll_clipboard_owner();

     return 1;}

   case SelectionRequest: {

@@ -1248,6 +1390,9 @@ int fl_handle(const XEvent& thisevent)

   case FocusIn:

     if (fl_xim_ic) XSetICFocus(fl_xim_ic);

     event = FL_FOCUS;

+    // If the user has toggled from another application to this one,

+    // then it's a good time to check for clipboard changes.

+    poll_clipboard_owner();

     break;

   case FocusOut: