Improve reliability of hotplugging window managers

* src/xterm.c (x_make_frame_visible): Change the user time
window if the window manager supports something different from
what it did the first time the frame was made visible.

1 files changed, 23 insertions, 8 deletions

diff --git a/src/xterm.c b/src/xterm.c
index 5b97da36ba1..abfad61041d 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -14534,21 +14534,36 @@ x_make_frame_visible (struct frame *f)
 #ifndef USE_GTK
       output = FRAME_X_OUTPUT (f);
 
-      if (output->user_time_window == None)
+      if (!x_wm_supports (f, dpyinfo->Xatom_net_wm_user_time_window))
         {
-          XSetWindowAttributes attrs;
-          memset (&attrs, 0, sizeof attrs);
-
-          output->user_time_window
-            = FRAME_OUTER_WINDOW (f);
-
-          if (x_wm_supports (f, dpyinfo->Xatom_net_wm_user_time_window))
+          if (output->user_time_window == None)
+            output->user_time_window = FRAME_OUTER_WINDOW (f);
+          else if (output->user_time_window != FRAME_OUTER_WINDOW (f))
+            {
+              XDestroyWindow (dpyinfo->display,
+                              output->user_time_window);
+              XDeleteProperty (dpyinfo->display,
+                               FRAME_OUTER_WINDOW (f),
+                               dpyinfo->Xatom_net_wm_user_time_window);
+              output->user_time_window = FRAME_OUTER_WINDOW (f);
+            }
+        }
+      else
+        {
+          if (output->user_time_window == FRAME_OUTER_WINDOW (f)
+              || output->user_time_window == None)
             {
+              XSetWindowAttributes attrs;
+              memset (&attrs, 0, sizeof attrs);
+
               output->user_time_window
                 = XCreateWindow (dpyinfo->display, FRAME_X_WINDOW (f),
                                  -1, -1, 1, 1, 0, 0, InputOnly,
                                  CopyFromParent, 0, &attrs);
 
+              XDeleteProperty (dpyinfo->display,
+                               FRAME_OUTER_WINDOW (f),
+                               dpyinfo->Xatom_net_wm_user_time);
               XChangeProperty (dpyinfo->display,
                                FRAME_OUTER_WINDOW (f),
                                dpyinfo->Xatom_net_wm_user_time_window,