avoid roundtrip * scale / scale

GUI/Model/Beam/BeamDistributionItem.cpp

@@ -52,9 +52,9 @@ void BeamDistributionItem::readFrom(QXmlStreamReader* r)
 
 double BeamDistributionItem::meanValue() const
 {
-    std::unique_ptr<IDistribution1D> domainDistr = createDistribution1D();
+    std::unique_ptr<IDistribution1D> domainDistr = distributionItem()->createDistribution(1.);
     if (domainDistr)
-        return domainDistr->mean() / scaleFactor();
+        return domainDistr->mean();
     return dynamic_cast<SymmetricDistributionItem*>(distributionItem())->mean().dVal();
 }