diff --git a/graphics/overlay.cpp b/graphics/overlay.cpp
index 96a87c2b17..76b0cdc364 100644
--- a/graphics/overlay.cpp
+++ b/graphics/overlay.cpp
@@ -385,13 +385,7 @@ namespace graphics
 
   void Overlay::deleteNotProcessed()
   {
-    for (set<OverlayElement *>::const_iterator it = m_notProcessedElements.begin();
-         it != m_notProcessedElements.end();
-         ++it)
-    {
-      delete *it;
-    }
-
+    for_each(m_notProcessedElements.begin(), m_notProcessedElements.end(), DeleteFunctor());
     m_notProcessedElements.clear();
   }
 
@@ -399,11 +393,13 @@ namespace graphics
   void Overlay::validateNotProcessed()
   {
     vector<OverlayElement *> v;
-
     m_tree.ForEach(MakeBackInsertFunctor(v));
+
     for (size_t i = 0; i < v.size(); ++i)
+    {
       ASSERT(m_notProcessedElements.find(v[i]) == m_notProcessedElements.end(),
              ("Object marked to deletion in tree!!!"));
+    }
   }
 #endif
 }
diff --git a/graphics/overlay.hpp b/graphics/overlay.hpp
index 3d4f892e3f..354b24fb14 100644
--- a/graphics/overlay.hpp
+++ b/graphics/overlay.hpp
@@ -45,7 +45,7 @@ namespace graphics
 
     struct Deleter
     {
-      void operator()(Overlay * overlay)
+      void operator()(Overlay * overlay) const
       {
         DeleteOverlay(overlay);
       }
@@ -115,7 +115,7 @@ namespace graphics
       m_threadID = id;
     }
 
-    bool validateTread(threads::ThreadID id)
+    bool validateThread(threads::ThreadID id)
     {
       return m_threadID == id;
     }
diff --git a/map/coverage_generator.cpp b/map/coverage_generator.cpp
index a18ee67612..2579f05f3f 100644
--- a/map/coverage_generator.cpp
+++ b/map/coverage_generator.cpp
@@ -218,7 +218,7 @@ void CoverageGenerator::CoverScreen(core::CommandsQueue::Environment const & env
   m_workCoverage->SetSequenceID(sequenceID);
   m_workCoverage->SetScreen(screen);
 #ifdef DEBUG
-  m_overlay.validateTread(threads::GetCurrentThreadID());
+  m_overlay.validateThread(threads::GetCurrentThreadID());
 #endif
   m_workCoverage->MergeOverlay(&m_overlay);
 
@@ -272,7 +272,7 @@ void CoverageGenerator::MergeTile(core::CommandsQueue::Environment const & env,
   m_currentCoverage->CopyInto(*m_workCoverage);
   m_workCoverage->SetSequenceID(sequenceID);
 #ifdef DEBUG
-  m_overlay.validateTread(threads::GetCurrentThreadID());
+  m_overlay.validateThread(threads::GetCurrentThreadID());
 #endif
   m_workCoverage->Merge(rectInfo, &m_overlay);