From 41f545287936cc3f31d443d09a60f656f8da6773 Mon Sep 17 00:00:00 2001
From: michl <michl@lazarus-ide.org>
Date: Wed, 20 Dec 2017 21:53:01 +0000
Subject: [PATCH] LCL: TNoteBook: Fixed TNotebook fires OnBeforeShow for
 destroying pages. Issue #32863. Patch by Rik van Kekem

git-svn-id: trunk@56811 -
---
 lcl/include/page.inc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lcl/include/page.inc b/lcl/include/page.inc
index e8b5b1bda1..ff370bbb57 100644
--- a/lcl/include/page.inc
+++ b/lcl/include/page.inc
@@ -33,7 +33,8 @@ begin
   end;
 
   //if old and new parent is a TNotebook then remove the page from the old one
-  if (OldParent <> nil) and (OldParent is TNotebook) then
+  if (OldParent <> nil) and (OldParent is TNotebook) and
+    not (csDestroying in OldParent.ComponentState) then
   begin
     // remove from old pagelist
     ParentNotebook := TNotebook(OldParent);
@@ -63,7 +64,8 @@ begin
   DebugLn('[TPage.Destroy]');
   {$endif}
 
-  if (Parent <> nil) and (Parent is TNotebook) then
+  if (Parent <> nil) and (Parent is TNotebook) and
+    not (csDestroying in Parent.ComponentState) then
   begin
     {$ifdef DEBUG_NEW_NOTEBOOK}
     DebugLn('[TPage.Destroy] FPages.Remove(Self)');