master cd18cee96e 2/2: Don't select for unnecessary properties during DND

[Po Lu]

branch: master
commit cd18cee96ee17562a276ea84bc9313e5bcbccb55
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Don't select for unnecessary properties during DND
    
    * src/xterm.c (x_dnd_begin_drag_and_drop): Don't select for
    property changes when not using toplevels.
---
 src/xterm.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/xterm.c b/src/xterm.c
index 8373222cfc..2643d1120f 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -11388,6 +11388,7 @@ x_dnd_begin_drag_and_drop (struct frame *f, Time time, 
Atom xaction,
 #ifndef USE_GTK
   struct x_display_info *event_display;
 #endif
+  unsigned int additional_mask;
 
   base = SPECPDL_INDEX ();
 
@@ -11598,7 +11599,7 @@ x_dnd_begin_drag_and_drop (struct frame *f, Time time, 
Atom xaction,
   if (EQ (return_frame, Qnow))
     x_dnd_return_frame = 2;
 
-  /* Now select for SubstructureNotifyMask and PropertyNotifyMask on
+  /* Now select for SubstructureNotifyMask and PropertyChangeMask on
      the root window, so we can get notified when window stacking
      changes, a common operation during drag-and-drop.  */
 
@@ -11606,11 +11607,15 @@ x_dnd_begin_drag_and_drop (struct frame *f, Time 
time, Atom xaction,
                        FRAME_DISPLAY_INFO (f)->root_window,
                        &root_window_attrs);
 
+  additional_mask = SubstructureNotifyMask;
+
+  if (x_dnd_use_toplevels)
+    additional_mask |= PropertyChangeMask;
+
   XSelectInput (FRAME_X_DISPLAY (f),
                FRAME_DISPLAY_INFO (f)->root_window,
                root_window_attrs.your_event_mask
-               | SubstructureNotifyMask
-               | PropertyChangeMask);
+               | additional_mask);
 
   if (EQ (return_frame, Qnow))
     x_dnd_update_state (FRAME_DISPLAY_INFO (f), CurrentTime);