3 files changed, 13 insertions, 6 deletions

diff --git a/src/haiku_support.cc b/src/haiku_support.cc
index b58420fcb99..a1616258bc3 100644
--- a/src/haiku_support.cc
+++ b/src/haiku_support.cc
@@ -4068,7 +4068,7 @@ be_drag_message_thread_entry (void *thread_data)
 }
 
 bool
-be_drag_message (void *view, void *message,
+be_drag_message (void *view, void *message, bool allow_same_view,
                  void (*block_input_function) (void),
                  void (*unblock_input_function) (void),
                  void (*process_pending_signals_function) (void),
@@ -4083,7 +4083,10 @@ be_drag_message (void *view, void *message,
   ssize_t stat;
 
   block_input_function ();
-  msg->AddInt32 ("emacs:window_id", window->window_id);
+
+  if (!allow_same_view)
+    msg->AddInt32 ("emacs:window_id", window->window_id);
+
   if (!vw->LockLooper ())
     gui_abort ("Failed to lock view looper for drag");
 
diff --git a/src/haiku_support.h b/src/haiku_support.h
index c978926e735..ae3ad6a68a8 100644
--- a/src/haiku_support.h
+++ b/src/haiku_support.h
@@ -944,7 +944,7 @@ extern "C"
   BMessage_delete (void *message);
 
   extern bool
-  be_drag_message (void *view, void *message,
+  be_drag_message (void *view, void *message, bool allow_same_view,
                    void (*block_input_function) (void),
                    void (*unblock_input_function) (void),
                    void (*process_pending_signals_function) (void),
diff --git a/src/haikuselect.c b/src/haikuselect.c
index 5540f467c0d..f1aa4f20d96 100644
--- a/src/haikuselect.c
+++ b/src/haikuselect.c
@@ -585,7 +585,7 @@ haiku_should_quit_drag (void)
 }
 
 DEFUN ("haiku-drag-message", Fhaiku_drag_message, Shaiku_drag_message,
-       2, 2, 0,
+       2, 3, 0,
        doc: /* Begin dragging MESSAGE from FRAME.
 
 MESSAGE an alist of strings, denoting message field names, to a list
@@ -606,8 +606,11 @@ associates to a 32-bit unsigned integer describing the type of the
 system message.
 
 FRAME is a window system frame that must be visible, from which the
-drag will originate.  */)
-  (Lisp_Object frame, Lisp_Object message)
+drag will originate.
+
+ALLOW-SAME-FRAME, if nil or not specified, means that MESSAGE will be
+ignored if it is dropped on top of FRAME.  */)
+  (Lisp_Object frame, Lisp_Object message, Lisp_Object allow_same_frame)
 {
   specpdl_ref idx;
   void *be_message;
@@ -625,6 +628,7 @@ drag will originate.  */)
   record_unwind_protect_ptr (BMessage_delete, be_message);
   haiku_lisp_to_message (message, be_message);
   rc = be_drag_message (FRAME_HAIKU_VIEW (f), be_message,
+                        !NILP (allow_same_frame),
                         block_input, unblock_input,
                         process_pending_signals,
                         haiku_should_quit_drag);