From a13b2b1de3fde7578aaa0771a83994638090bea5 Mon Sep 17 00:00:00 2001
From: Enrico Turri <enricoturri@seznam.cz>
Date: Tue, 9 Apr 2019 11:18:40 +0200
Subject: [PATCH] Fixed crash when using mouse wheel before the 3D scene is
 shown (during app startup)

---
 src/slic3r/GUI/GLCanvas3D.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index b8f724320..e97b819a0 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -2313,6 +2313,9 @@ void GLCanvas3D::on_key(wxKeyEvent& evt)
 
 void GLCanvas3D::on_mouse_wheel(wxMouseEvent& evt)
 {
+    if (!m_initialized)
+        return;
+
     // Ignore the wheel events if the middle button is pressed.
     if (evt.MiddleIsDown())
         return;