From 5be1f8f20910970c31db9bb131d312960c941f13 Mon Sep 17 00:00:00 2001
From: SoftFever <softfeverever@gmail.com>
Date: Wed, 19 Aug 2026 01:37:23 +0800
Subject: [PATCH] fix crash on Mac

---
 src/slic3r/GUI/Monitor.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/slic3r/GUI/Monitor.cpp b/src/slic3r/GUI/Monitor.cpp
index 51bd7ed878..1a6d969988 100644
--- a/src/slic3r/GUI/Monitor.cpp
+++ b/src/slic3r/GUI/Monitor.cpp
@@ -413,7 +413,10 @@ void MonitorPanel::update_hms_tag()
 bool MonitorPanel::Show(bool show)
 {
 #ifdef __APPLE__
-    wxGetApp().mainframe->SetMinSize(wxGetApp().plater()->GetMinSize());
+    // Notebook::InsertPage() hides every page it appends, so this also runs while MainFrame is
+    // still constructing, before GUI_App::mainframe is assigned. Same guard as Plater::Show().
+    if (wxGetApp().mainframe)
+        wxGetApp().mainframe->SetMinSize(wxGetApp().plater()->GetMinSize());
 #endif
 
     NetworkAgent* m_agent = wxGetApp().getAgent();