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.

1 files changed, 8 insertions, 3 deletions

diff --git a/src/xterm.c b/src/xterm.c
index 8373222cfc3..2643d1120f9 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);