Fix bug #13953 with spontaneous frame resizes on MS-Windows.

 src/w32term.c (w32_read_socket) <WM_WINDOWPOSCHANGED>: Remove old
 and incorrect code.  Treat WM_WINDOWPOSCHANGED like WM_ACTIVATE
 and WM_ACTIVATEAPP.
 (w32fullscreen_hook): If the frame is visible, reset
 f->want_fullscreen flag after changing the frame size.  If the
 frame is not visible, set f->want_fullscreen to FULLSCREEN_WAIT.

1 files changed, 12 insertions, 15 deletions

diff --git a/src/w32term.c b/src/w32term.c
index 680ad668ab3..6b51777839f 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -4705,26 +4705,20 @@ w32_read_socket (struct terminal *terminal,
 	  }
 
 	case WM_WINDOWPOSCHANGED:
-	  f = x_window_to_frame (dpyinfo, msg.msg.hwnd);
-	  if (f)
-	    {
-	      if (f->want_fullscreen & FULLSCREEN_WAIT)
-		f->want_fullscreen &= ~(FULLSCREEN_WAIT|FULLSCREEN_BOTH);
-	    }
-	  check_visibility = 1;
-	  break;
-
 	case WM_ACTIVATE:
 	case WM_ACTIVATEAPP:
 	  f = x_window_to_frame (dpyinfo, msg.msg.hwnd);
 	  if (f)
 	    {
-	      /* If we are being activated, run the full-screen hook
-		 function, to actually install the required size in
-		 effect.  This is because when the hook is run from
-		 x_set_fullscreen, the frame might not yet be visible,
-		 if that call is a result of make-frame.  */
-	      if (msg.msg.wParam)
+	      /* Run the full-screen hook function also when we are
+		 being activated, to actually install the required
+		 size in effect, if the WAIT flag is set.  This is
+		 because when the hook is run from x_set_fullscreen,
+		 the frame might not yet be visible, if that call is a
+		 result of make-frame, and in that case the hook just
+		 sets the WAIT flag.  */
+	      if ((msg.msg.message == WM_WINDOWPOSCHANGED || msg.msg.wParam)
+		  && (f->want_fullscreen & FULLSCREEN_WAIT))
 		w32fullscreen_hook (f);
 	      x_check_fullscreen (f);
 	    }
@@ -5739,8 +5733,11 @@ w32fullscreen_hook (FRAME_PTR f)
 	  x_set_window_size (f, 1, width, height);
 	  do_pending_window_change (0);
 	}
+      f->want_fullscreen = FULLSCREEN_NONE;
       unblock_input ();
     }
+  else
+    f->want_fullscreen |= FULLSCREEN_WAIT;
 }
 
 /* Call this to change the size of frame F's x-window.