From 830ac027c9906e3d93cb9fa8d848188ed5e8a3fc Mon Sep 17 00:00:00 2001
From: Juha <juha@lazarus-ide.org>
Date: Sat, 24 Aug 2024 21:12:58 +0300
Subject: [PATCH] LCL: Prevent crash in RadioGroup when hidden radiobutton is
 selected by arrow keys. Issue #41093.

(cherry picked from commit 48cf66858d9c31a57caf416ddc053760eef85243)
---
 lcl/include/radiogroup.inc | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lcl/include/radiogroup.inc b/lcl/include/radiogroup.inc
index c37fb3ed5a..33caa17f99 100644
--- a/lcl/include/radiogroup.inc
+++ b/lcl/include/radiogroup.inc
@@ -264,6 +264,7 @@ procedure TCustomRadioGroup.ItemKeyDown(Sender: TObject; var Key: Word;
     BlockSize : integer;
     NewIndex : integer;
     WrapOffset: integer;
+    Butt: TRadioButton;
   begin
     Count := FButtonList.Count;
     if FColumnLayout=clHorizontalThenVertical then begin
@@ -287,9 +288,11 @@ procedure TCustomRadioGroup.ItemKeyDown(Sender: TObject; var Key: Word;
         while NewIndex >= Count do
            NewIndex := (NewIndex + StepSize) mod BlockSize;
       end;
-    until (NewIndex = ItemIndex) or TRadioButton(FButtonList[NewIndex]).Enabled;
+      Butt := TRadioButton(FButtonList[NewIndex]);
+    until (NewIndex = ItemIndex) or (Butt.Visible and Butt.Enabled);
     ItemIndex := NewIndex;
-    TRadioButton(FButtonList[ItemIndex]).SetFocus;
+    if Butt.CanSetFocus then  // ItemIndex = NewIndex, Butt is still valid.
+      Butt.SetFocus;
     Key := 0;
   end;