diff --git a/src/slic3r/GUI/GCodeViewer.cpp b/src/slic3r/GUI/GCodeViewer.cpp
index e21ba7f00..f744bb6e8 100644
--- a/src/slic3r/GUI/GCodeViewer.cpp
+++ b/src/slic3r/GUI/GCodeViewer.cpp
@@ -434,10 +434,26 @@ void GCodeViewer::reset()
 
 void GCodeViewer::render() const
 {
+    auto init_gl_data = [this]() {
+        static bool first_run = true;
+        if (first_run) {
+            m_sequential_view.marker.init();
+
+            std::array<int, 2> point_sizes;
+            ::glGetIntegerv(GL_ALIASED_POINT_SIZE_RANGE, point_sizes.data());
+            m_detected_point_sizes = { static_cast<float>(point_sizes[0]), static_cast<float>(point_sizes[1]) };
+            first_run = false;
+        }
+    };
+
 #if ENABLE_GCODE_VIEWER_STATISTICS
     m_statistics.reset_opengl();
 #endif // ENABLE_GCODE_VIEWER_STATISTICS
 
+    // OpenGL data must be initialized after the glContext has been created.
+    // This is ensured when this method is called by GLCanvas3D::_render_gcode().
+    init_gl_data();
+
     if (m_roles.empty())
         return;
 
@@ -893,13 +909,8 @@ void GCodeViewer::init()
     }
 
     set_toolpath_move_type_visible(EMoveType::Extrude, true);
-    m_sequential_view.marker.init();
 //    m_sequential_view.skip_invisible_moves = true;
 
-    std::array<int, 2> point_sizes;
-    ::glGetIntegerv(GL_ALIASED_POINT_SIZE_RANGE, point_sizes.data());
-    m_detected_point_sizes = { static_cast<float>(point_sizes[0]), static_cast<float>(point_sizes[1]) };
-
     m_initialized = true;
 }
 
diff --git a/src/slic3r/GUI/GCodeViewer.hpp b/src/slic3r/GUI/GCodeViewer.hpp
index 4ae5cf2dd..1cf538584 100644
--- a/src/slic3r/GUI/GCodeViewer.hpp
+++ b/src/slic3r/GUI/GCodeViewer.hpp
@@ -410,7 +410,7 @@ private:
 #if ENABLE_GCODE_VIEWER_STATISTICS
     mutable Statistics m_statistics;
 #endif // ENABLE_GCODE_VIEWER_STATISTICS
-    std::array<float, 2> m_detected_point_sizes = { 0.0f, 0.0f };
+    mutable std::array<float, 2> m_detected_point_sizes = { 0.0f, 0.0f };
 
 public:
     GCodeViewer() = default;
diff --git a/src/slic3r/GUI/OpenGLManager.cpp b/src/slic3r/GUI/OpenGLManager.cpp
index 13c58f847..4f1e00793 100644
--- a/src/slic3r/GUI/OpenGLManager.cpp
+++ b/src/slic3r/GUI/OpenGLManager.cpp
@@ -234,10 +234,8 @@ OpenGLManager::~OpenGLManager()
 
 bool OpenGLManager::init_gl()
 {
-    if (!m_gl_initialized)
-    {
-        if (glewInit() != GLEW_OK)
-        {
+    if (!m_gl_initialized) {
+        if (glewInit() != GLEW_OK) {
             BOOST_LOG_TRIVIAL(error) << "Unable to init glew library";
             return false;
         }