--- a/QTfrontend/ui/widget/drawmapwidget.cpp	Sat Mar 17 17:47:42 2018 +0100
+++ b/QTfrontend/ui/widget/drawmapwidget.cpp	Sat Mar 17 23:55:32 2018 +0300
@@ -63,6 +63,9 @@
 {
     Q_UNUSED(event);
 
+	if(!m_scene)
+		return;
+		
     int height = this->height();
     int width = this->width();