master fbe7ac16d7: Fix replying to _NET_WM_PING during drag-and-drop

[Po Lu]

branch: master
commit fbe7ac16d722f786e5f3f2e3a916b1aa79510eb5
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Fix replying to _NET_WM_PING during drag-and-drop
    
    * src/xterm.c (handle_one_xevent): Test client window against
    root window instead of using nonstandard event mask.
---
 src/xterm.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/src/xterm.c b/src/xterm.c
index 0ebabdccaf..fb7d18a53f 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -15246,25 +15246,23 @@ handle_one_xevent (struct x_display_info *dpyinfo,
 
 
            if (event->xclient.data.l[0] == dpyinfo->Xatom_net_wm_ping
+               /* Handling window stacking changes during
+                  drag-and-drop requires Emacs to select for
+                  SubstructureNotifyMask, which in turn causes the
+                  message to be sent to Emacs itself using the event
+                  mask specified by the EWMH.  To avoid an infinite
+                  loop, make sure the client message's window is not
+                  the root window if DND is in progress.  */
+               && (!x_dnd_in_progress
+                   || !x_dnd_waiting_for_finish
+                   || event->xclient.window != dpyinfo->root_window)
                && event->xclient.format == 32)
              {
                XEvent send_event = *event;
 
                send_event.xclient.window = dpyinfo->root_window;
                XSendEvent (dpyinfo->display, dpyinfo->root_window, False,
-                           /* FIXME: handling window stacking changes
-                              during drag-and-drop requires Emacs to
-                              select for SubstructureNotifyMask,
-                              which in turn causes the message to be
-                              sent to Emacs itself using the event
-                              mask specified by the EWMH.  To avoid
-                              an infinite loop, just use
-                              SubstructureRedirectMask when a
-                              drag-and-drop operation is in
-                              progress.  */
-                           ((x_dnd_in_progress || x_dnd_waiting_for_finish)
-                            ? SubstructureRedirectMask
-                            : SubstructureRedirectMask | 
SubstructureNotifyMask),
+                           SubstructureRedirectMask | SubstructureNotifyMask,
                            &send_event);
 
                *finish = X_EVENT_DROP;