From ffac9368820d021978d58db0ac33b2e60ab0871e Mon Sep 17 00:00:00 2001
From: Paul Cornett <paulcor@users.noreply.github.com>
Date: Tue, 22 Oct 2019 19:51:50 -0700
Subject: [PATCH] Fix crash in propgrid sample, see #18537

---
 samples/propgrid/propgrid.cpp | 48 +++++++++++++++++++----------------
 1 file changed, 26 insertions(+), 22 deletions(-)

diff --git a/samples/propgrid/propgrid.cpp b/samples/propgrid/propgrid.cpp
index d1382516aa..4cce1563e2 100644
--- a/samples/propgrid/propgrid.cpp
+++ b/samples/propgrid/propgrid.cpp
@@ -2985,21 +2985,23 @@ void FormMain::OnSetPropertyValue( wxCommandEvent& WXUNUSED(event) )
 void FormMain::OnInsertChoice( wxCommandEvent& WXUNUSED(event) )
 {
     wxPropertyGrid* pg = m_pPropGridManager->GetGrid();
-
     wxPGProperty* selected = pg->GetSelection();
-    const wxPGChoices& choices = selected->GetChoices();
 
-    // Insert new choice to the center of list
+    if (selected)
+    {
+        const wxPGChoices& choices = selected->GetChoices();
 
-    if ( choices.IsOk() )
-    {
-        int pos = choices.GetCount() / 2;
-        selected->InsertChoice("New Choice", pos);
-    }
-    else
-    {
-        ::wxMessageBox("First select a property with some choices.");
+        if ( choices.IsOk() )
+        {
+            // Insert new choice to the center of list
+
+            int pos = choices.GetCount() / 2;
+            selected->InsertChoice("New Choice", pos);
+            return;
+        }
     }
+
+    wxMessageBox("First select a property with some choices.");
 }
 
 // -----------------------------------------------------------------------
@@ -3007,21 +3009,23 @@ void FormMain::OnInsertChoice( wxCommandEvent& WXUNUSED(event) )
 void FormMain::OnDeleteChoice( wxCommandEvent& WXUNUSED(event) )
 {
     wxPropertyGrid* pg = m_pPropGridManager->GetGrid();
-
     wxPGProperty* selected = pg->GetSelection();
-    const wxPGChoices& choices = selected->GetChoices();
 
-    // Deletes choice from the center of list
+    if (selected)
+    {
+        const wxPGChoices& choices = selected->GetChoices();
 
-    if ( choices.IsOk() )
-    {
-        int pos = choices.GetCount() / 2;
-        selected->DeleteChoice(pos);
-    }
-    else
-    {
-        ::wxMessageBox("First select a property with some choices.");
+        if ( choices.IsOk() )
+        {
+            // Deletes choice from the center of list
+
+            int pos = choices.GetCount() / 2;
+            selected->DeleteChoice(pos);
+            return;
+        }
     }
+
+    wxMessageBox("First select a property with some choices.");
 }
 
 // -----------------------------------------------------------------------