From 20cff0f630d37181beabec8baa7010f2b90c8ed1 Mon Sep 17 00:00:00 2001
From: Enrico Turri <enricoturri@seznam.cz>
Date: Fri, 7 Dec 2018 09:00:17 +0100
Subject: [PATCH] Fixed crash when selecting wipe tower

---
 src/slic3r/GUI/GLCanvas3D.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index f18b1e71c..3fc090c6b 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -1383,7 +1383,7 @@ bool GLCanvas3D::Selection::is_single_full_instance() const
         return false;
 
     int object_idx = m_valid ? get_object_idx() : -1;
-    if (object_idx == -1)
+    if ((object_idx < 0) || ((int)m_model->objects.size() < object_idx))
         return false;
 
     int instance_idx = (*m_volumes)[*m_list.begin()]->instance_idx();