diff --git a/ArchitectureColoredPainting/src/Editor/LayerStyle.cpp b/ArchitectureColoredPainting/src/Editor/LayerStyle.cpp
index a6dc9d8..c57ea2f 100644
--- a/ArchitectureColoredPainting/src/Editor/LayerStyle.cpp
+++ b/ArchitectureColoredPainting/src/Editor/LayerStyle.cpp
@@ -194,18 +194,23 @@ bool LayerStyleContainer::dropStyle(const QString& styleName)
 	return true;
 }
 
-float LayerStyleContainer::boundingBoxAffectValue() {
+float LayerStyleContainer::boundingBoxAffectValue() const {
     float maxLineWidth = 0;
-    auto strokeStyle = styles[StrokeElementLayerStyle::displayName()];
-    if (strokeStyle != nullptr) {
-        auto strokeElementLayerStyle = dynamic_cast<StrokeElementLayerStyle*>(strokeStyle.get());
-        if (strokeElementLayerStyle != nullptr) {
-            auto leftStyleStroke = strokeElementLayerStyle->strokePair.first;
-            auto rightStyleStroke = strokeElementLayerStyle->strokePair.second;
-            if (leftStyleStroke != nullptr) {
+    const auto strokeStyle = styles.at(StrokeElementLayerStyle::displayName());
+    if (strokeStyle != nullptr)
+    {
+        if (const auto strokeElementLayerStyle =
+				std::dynamic_pointer_cast<StrokeElementLayerStyle>(strokeStyle);
+            strokeElementLayerStyle != nullptr)
+        {
+            const auto& leftStyleStroke = strokeElementLayerStyle->strokePair.first;
+            const auto& rightStyleStroke = strokeElementLayerStyle->strokePair.second;
+            if (leftStyleStroke != nullptr)
+            {
                 maxLineWidth = std::max(maxLineWidth, leftStyleStroke->halfWidth);
             }
-            if (rightStyleStroke != nullptr) {
+            if (rightStyleStroke != nullptr)
+            {
                 maxLineWidth = std::max(maxLineWidth, rightStyleStroke->halfWidth);
             }
         }
diff --git a/ArchitectureColoredPainting/src/Editor/LayerStyle.h b/ArchitectureColoredPainting/src/Editor/LayerStyle.h
index 780b207..6db22d6 100644
--- a/ArchitectureColoredPainting/src/Editor/LayerStyle.h
+++ b/ArchitectureColoredPainting/src/Editor/LayerStyle.h
@@ -65,7 +65,7 @@ public:
     std::unique_ptr<LayerStyle> makeUnusedStyle(const QString& styleName) const;
     bool useStyle(const std::shared_ptr<LayerStyle>& style);
     bool dropStyle(const QString& styleName);
-    float boundingBoxAffectValue();
+    float boundingBoxAffectValue() const;
     size_t getHash() const;
 
     /**