From a012c5158d34d34cb42e807c2636cd56976323bb Mon Sep 17 00:00:00 2001
From: wp_xxyyzz <wp_xxyyzz@8e941d3f-bd1b-0410-a28a-d453659cc2b4>
Date: Sat, 27 Apr 2019 17:26:49 +0000
Subject: [PATCH] jvcllaz: Fix TJvDBTreeView and TJvDBLookupTreeView crashing
 the IDE when they are deleted from the form.

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@6871 8e941d3f-bd1b-0410-a28a-d453659cc2b4
---
 components/jvcllaz/run/JvDB/JvDBTreeView.pas | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/components/jvcllaz/run/JvDB/JvDBTreeView.pas b/components/jvcllaz/run/JvDB/JvDBTreeView.pas
index beb536ffd..3b8109827 100644
--- a/components/jvcllaz/run/JvDB/JvDBTreeView.pas
+++ b/components/jvcllaz/run/JvDB/JvDBTreeView.pas
@@ -1581,7 +1581,9 @@ var
   strLength: Integer;
   HasChildren: Byte;
 begin
-  if Items.Count > 0 then
+  // wp: not clear if this still works correctly: had to add "Assigned(Items)"
+  // to prevent crash when destroying
+  if Assigned(Items) and (Items.Count > 0) then
   begin
     // save master values into stream
     FMastersStream := TMemoryStream.Create;