master 6aa8baaea1: Use cached monitor info during DND if available

[Po Lu]

branch: master
commit 6aa8baaea1b872a9b770d680849b9b1b95eb2840
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Use cached monitor info during DND if available
    
    * src/xterm.c (x_dnd_begin_drag_and_drop): Use previously cached
    monitor attributes if they exist.
---
 src/xterm.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/xterm.c b/src/xterm.c
index f422fc9d40..e282856374 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -10988,8 +10988,15 @@ x_dnd_begin_drag_and_drop (struct frame *f, Time time, 
Atom xaction,
 
   if (follow_tooltip)
     {
+#if defined HAVE_XRANDR || defined USE_GTK
       x_dnd_monitors
-       = Fx_display_monitor_attributes_list (frame);
+       = FRAME_DISPLAY_INFO (f)->last_monitor_attributes_list;
+
+      if (NILP (x_dnd_monitors))
+#endif
+       x_dnd_monitors
+         = Fx_display_monitor_attributes_list (frame);
+
       record_unwind_protect_void (x_clear_dnd_monitors);
     }