diff --git a/mix/ClientModel.cpp b/mix/ClientModel.cpp
index 61a3dee1f..717757c70 100644
--- a/mix/ClientModel.cpp
+++ b/mix/ClientModel.cpp
@@ -422,7 +422,7 @@ void ClientModel::showDebuggerForTransaction(ExecutionResult const& _t)
 		//try to resolve contract for source level debugging
 		auto nameIter = m_contractNames.find(code.address);
 		CompiledContract const* compilerRes = nullptr;
-		if (nameIter != m_contractNames.end() && (compilerRes = m_codeModel->tryGetContract(nameIter->second)))
+		if (nameIter != m_contractNames.end() && (compilerRes = m_codeModel->tryGetContract(nameIter->second))) //returned object is guaranteed to live till the end of event handler in main thread
 		{
 			eth::AssemblyItems assemblyItems = !_t.isConstructor() ? compilerRes->assemblyItems() : compilerRes->constructorAssemblyItems();
 			codes.back()->setDocument(compilerRes->documentId());
@@ -467,9 +467,9 @@ void ClientModel::showDebuggerForTransaction(ExecutionResult const& _t)
 			{
 				//track calls into functions
 				AssemblyItem const& prevInstruction = codeItems[s.codeIndex][prevInstructionIndex];
-				auto functionIter = contract->functions().find(LocationPair(instruction.getLocation().start, instruction.getLocation().end));
-				if (functionIter != contract->functions().end() && ((prevInstruction.getJumpType() == AssemblyItem::JumpType::IntoFunction) || solCallStack.empty()))
-					solCallStack.push_front(QVariant::fromValue(functionIter.value()));
+				QString functionName = m_codeModel->resolveFunctionName(instruction.getLocation());
+				if (!functionName.isEmpty() && ((prevInstruction.getJumpType() == AssemblyItem::JumpType::IntoFunction) || solCallStack.empty()))
+					solCallStack.push_front(QVariant::fromValue(functionName));
 				else if (prevInstruction.getJumpType() == AssemblyItem::JumpType::OutOfFunction && !solCallStack.empty())
 					solCallStack.pop_front();
 			}
@@ -521,11 +521,13 @@ void ClientModel::showDebuggerForTransaction(ExecutionResult const& _t)
 
 			prevInstructionIndex = instructionIndex;
 
+			// filter out locations that match whole function or contract
 			SourceLocation location = instruction.getLocation();
-			if (contract->contract()->location() == location || contract->functions().contains(LocationPair(location.start, location.end)))
+			QString source = QString::fromUtf8(location.sourceName->c_str());
+			if (m_codeModel->isContractOrFunctionLocation(location))
 				location = dev::SourceLocation(-1, -1, location.sourceName);
 
-			solState = new QSolState(debugData, move(storage), move(solCallStack), move(locals), location.start, location.end, QString::fromUtf8(location.sourceName->c_str()));
+			solState = new QSolState(debugData, move(storage), move(solCallStack), move(locals), location.start, location.end, source);
 		}
 
 		states.append(QVariant::fromValue(new QMachineState(debugData, instructionIndex, s, codes[s.codeIndex], data[s.dataIndex], solState)));
diff --git a/mix/CodeModel.cpp b/mix/CodeModel.cpp
index 357ce88b9..515123de5 100644
--- a/mix/CodeModel.cpp
+++ b/mix/CodeModel.cpp
@@ -51,30 +51,31 @@ const std::set<std::string> c_predefinedContracts =
 namespace
 {
 using namespace dev::solidity;
-class CollectDeclarationsVisitor: public ASTConstVisitor
+
+class CollectLocalsVisitor: public ASTConstVisitor
 {
 public:
-	CollectDeclarationsVisitor(QHash<LocationPair, QString>* _functions, QHash<LocationPair, SolidityDeclaration>* _locals):
-	m_functions(_functions), m_locals(_locals), m_functionScope(false) {}
+	CollectLocalsVisitor(QHash<LocationPair, SolidityDeclaration>* _locals):
+	m_locals(_locals), m_functionScope(false) {}
+
 private:
 	LocationPair nodeLocation(ASTNode const& _node)
 	{
 		return LocationPair(_node.getLocation().start, _node.getLocation().end);
 	}
 
-	virtual bool visit(FunctionDefinition const& _node)
+	virtual bool visit(FunctionDefinition const&)
 	{
-		m_functions->insert(nodeLocation(_node), QString::fromStdString(_node.getName()));
 		m_functionScope = true;
 		return true;
 	}
 
-	virtual void endVisit(FunctionDefinition const&)
+	virtual void endVisit(FunctionDefinition const&) override
 	{
 		m_functionScope = false;
 	}
 
-	virtual bool visit(VariableDeclaration const& _node)
+	virtual bool visit(VariableDeclaration const& _node) override
 	{
 		SolidityDeclaration decl;
 		decl.type = CodeModel::nodeType(_node.getType().get());
@@ -87,11 +88,38 @@ private:
 	}
 
 private:
-	QHash<LocationPair, QString>* m_functions;
 	QHash<LocationPair, SolidityDeclaration>* m_locals;
 	bool m_functionScope;
 };
 
+class CollectLocationsVisitor: public ASTConstVisitor
+{
+public:
+	CollectLocationsVisitor(SourceMap* _sourceMap):
+	m_sourceMap(_sourceMap) {}
+
+private:
+	LocationPair nodeLocation(ASTNode const& _node)
+	{
+		return LocationPair(_node.getLocation().start, _node.getLocation().end);
+	}
+
+	virtual bool visit(FunctionDefinition const& _node) override
+	{
+		m_sourceMap->functions.insert(nodeLocation(_node), QString::fromStdString(_node.getName()));
+		return true;
+	}
+
+	virtual bool visit(ContractDefinition const& _node) override
+	{
+		m_sourceMap->contracts.insert(nodeLocation(_node), QString::fromStdString(_node.getName()));
+		return true;
+	}
+
+private:
+	SourceMap* m_sourceMap;
+};
+
 QHash<unsigned, SolidityDeclarations> collectStorage(dev::solidity::ContractDefinition const& _contract)
 {
 	QHash<unsigned, SolidityDeclarations> result;
@@ -132,7 +160,7 @@ CompiledContract::CompiledContract(const dev::solidity::CompilerStack& _compiler
 	if (contractDefinition.getLocation().sourceName.get())
 		m_documentId = QString::fromStdString(*contractDefinition.getLocation().sourceName);
 
-	CollectDeclarationsVisitor visitor(&m_functions, &m_locals);
+	CollectLocalsVisitor visitor(&m_locals);
 	m_storage = collectStorage(contractDefinition);
 	contractDefinition.accept(visitor);
 	m_assemblyItems = *_compiler.getRuntimeAssemblyItems(name);
@@ -243,6 +271,7 @@ void CodeModel::releaseContracts()
 	for (ContractMap::iterator c = m_contractMap.begin(); c != m_contractMap.end(); ++c)
 		c.value()->deleteLater();
 	m_contractMap.clear();
+	m_sourceMaps.clear();
 }
 
 void CodeModel::runCompilationJob(int _jobId)
@@ -253,13 +282,17 @@ void CodeModel::runCompilationJob(int _jobId)
 	try
 	{
 		cs.addSource("configUser", R"(contract configUser{function configAddr()constant returns(address a){ return 0xf025d81196b72fba60a1d4dddad12eeb8360d828;}})");
+		std::vector<std::string> sourceNames;
 		{
 			Guard l(x_pendingContracts);
 			for (auto const& c: m_pendingContracts)
+			{
 				cs.addSource(c.first.toStdString(), c.second.toStdString());
+				sourceNames.push_back(c.first.toStdString());
+			}
 		}
 		cs.compile(false);
-		collectContracts(cs);
+		collectContracts(cs, sourceNames);
 	}
 	catch (dev::Exception const& _exception)
 	{
@@ -281,11 +314,20 @@ void CodeModel::runCompilationJob(int _jobId)
 	emit stateChanged();
 }
 
-void CodeModel::collectContracts(dev::solidity::CompilerStack const& _cs)
+void CodeModel::collectContracts(dev::solidity::CompilerStack const& _cs, std::vector<std::string> const& _sourceNames)
 {
 	Guard pl(x_pendingContracts);
 	Guard l(x_contractMap);
 	ContractMap result;
+	SourceMaps sourceMaps;
+	for (std::string const& sourceName: _sourceNames)
+	{
+		dev::solidity::SourceUnit const& source = _cs.getAST(sourceName);
+		SourceMap sourceMap;
+		CollectLocationsVisitor collector(&sourceMap);
+		source.accept(collector);
+		sourceMaps.insert(QString::fromStdString(sourceName), std::move(sourceMap));
+	}
 	for (std::string n: _cs.getContractNames())
 	{
 		if (c_predefinedContracts.count(n) != 0)
@@ -326,6 +368,7 @@ void CodeModel::collectContracts(dev::solidity::CompilerStack const& _cs)
 	}
 	releaseContracts();
 	m_contractMap.swap(result);
+	m_sourceMaps.swap(sourceMaps);
 	emit codeChanged();
 	emit compilationComplete();
 }
@@ -431,3 +474,32 @@ SolidityType CodeModel::nodeType(dev::solidity::Type const* _type)
 	return r;
 }
 
+bool CodeModel::isContractOrFunctionLocation(dev::SourceLocation const& _location)
+{
+	if (!_location.sourceName)
+		return false;
+	Guard l(x_contractMap);
+	auto sourceMapIter = m_sourceMaps.find(QString::fromStdString(*_location.sourceName));
+	if (sourceMapIter != m_sourceMaps.cend())
+	{
+		LocationPair location(_location.start, _location.end);
+		return sourceMapIter.value().contracts.contains(location) || sourceMapIter.value().functions.contains(location);
+	}
+	return false;
+}
+
+QString CodeModel::resolveFunctionName(dev::SourceLocation const& _location)
+{
+	if (!_location.sourceName)
+		return QString();
+	Guard l(x_contractMap);
+	auto sourceMapIter = m_sourceMaps.find(QString::fromStdString(*_location.sourceName));
+	if (sourceMapIter != m_sourceMaps.cend())
+	{
+		LocationPair location(_location.start, _location.end);
+		auto functionNameIter = sourceMapIter.value().functions.find(location);
+		if (functionNameIter != sourceMapIter.value().functions.cend())
+			return functionNameIter.value();
+	}
+	return QString();
+}
diff --git a/mix/CodeModel.h b/mix/CodeModel.h
index 0572483c0..3c6c3abdf 100644
--- a/mix/CodeModel.h
+++ b/mix/CodeModel.h
@@ -97,7 +97,6 @@ public:
 	/// @returns contract source Id
 	QString documentId() const { return m_documentId; }
 
-	QHash<LocationPair, QString> const& functions() const { return m_functions; }
 	QHash<LocationPair, SolidityDeclaration> const& locals() const { return m_locals; }
 	QHash<unsigned, SolidityDeclarations> const& storage() const { return m_storage; }
 
@@ -110,7 +109,6 @@ private:
 	QString m_documentId;
 	eth::AssemblyItems m_assemblyItems;
 	eth::AssemblyItems m_constructorAssemblyItems;
-	QHash<LocationPair, QString> m_functions;
 	QHash<LocationPair, SolidityDeclaration> m_locals;
 	QHash<unsigned, SolidityDeclarations> m_storage;
 
@@ -119,6 +117,17 @@ private:
 
 using ContractMap = QMap<QString, CompiledContract*>; //needs to be sorted
 
+/// Source map
+using LocationMap = QHash<LocationPair, QString>;
+
+struct SourceMap
+{
+	LocationMap contracts;
+	LocationMap functions;
+};
+
+using SourceMaps = QMap<QString, SourceMap>; //by source id
+
 /// Code compilation model. Compiles contracts in background an provides compiled contract data
 class CodeModel: public QObject
 {
@@ -153,6 +162,10 @@ public:
 	Q_INVOKABLE void reset() { reset(QVariantMap()); }
 	/// Convert solidity type info to mix type
 	static SolidityType nodeType(dev::solidity::Type const* _type);
+	/// Check if given location belongs to contract or function
+	bool isContractOrFunctionLocation(dev::SourceLocation const& _location);
+	/// Get funciton name by location
+	QString resolveFunctionName(dev::SourceLocation const& _location);
 
 signals:
 	/// Emited on compilation state change
@@ -182,11 +195,12 @@ private:
 	void runCompilationJob(int _jobId);
 	void stop();
 	void releaseContracts();
-	void collectContracts(solidity::CompilerStack const& _cs);
+	void collectContracts(dev::solidity::CompilerStack const& _cs, std::vector<std::string> const& _sourceNames);
 
 	std::atomic<bool> m_compiling;
 	mutable dev::Mutex x_contractMap;
 	ContractMap m_contractMap;
+	SourceMaps m_sourceMaps;
 	std::unique_ptr<CodeHighlighterSettings> m_codeHighlighterSettings;
 	QThread m_backgroundThread;
 	BackgroundWorker m_backgroundWorker;
diff --git a/mix/qml/StateDialog.qml b/mix/qml/StateDialog.qml
index 3a3a060c3..13d01d474 100644
--- a/mix/qml/StateDialog.qml
+++ b/mix/qml/StateDialog.qml
@@ -158,7 +158,7 @@ Dialog {
 								id: importJsonFileDialog
 								visible: false
 								title: qsTr("Select State File")
-								nameFilters: [qsTr("JSON files (*.json)", "All files (*)")]
+								nameFilters: Qt.platform.os === "osx" ? [] : [qsTr("JSON files (*.json)", "All files (*)")] //qt 5.4 segfaults with filter string on OSX
 								onAccepted: {
 									var path = importJsonFileDialog.fileUrl.toString()
 									var jsonData = fileIo.readFile(path)
diff --git a/mix/qml/html/codeeditor.js b/mix/qml/html/codeeditor.js
index e8504fee0..d25fbd091 100644
--- a/mix/qml/html/codeeditor.js
+++ b/mix/qml/html/codeeditor.js
@@ -126,7 +126,10 @@ highlightExecution = function(start, end) {
 		executionMark.clear();
 	if (debugWarning)
 		debugWarning.clear();
-	executionMark = editor.markText(editor.posFromIndex(start), editor.posFromIndex(end), { className: "CodeMirror-exechighlight" });
+	if (start > 0 && end > start) {
+		executionMark = editor.markText(editor.posFromIndex(start), editor.posFromIndex(end), { className: "CodeMirror-exechighlight" });
+		editor.scrollIntoView(editor.posFromIndex(start));
+	}
 }
 
 var changeId;
diff --git a/mix/qml/js/Debugger.js b/mix/qml/js/Debugger.js
index 3f5742fde..f6900489a 100644
--- a/mix/qml/js/Debugger.js
+++ b/mix/qml/js/Debugger.js
@@ -183,7 +183,8 @@ function selectState(stateIndex)
 
 function highlightSelection(index)
 {
-	statesList.positionViewAtRow(index, ListView.Center);
+	if (statesList.visible)
+		statesList.positionViewAtRow(index, ListView.Visible);
 	statesList.selection.clear();
 	statesList.selection.select(index);
 }
diff --git a/mix/test/qml/js/TestTutorial.js b/mix/test/qml/js/TestTutorial.js
index 7f366f23b..895b5c9c1 100644
--- a/mix/test/qml/js/TestTutorial.js
+++ b/mix/test/qml/js/TestTutorial.js
@@ -52,7 +52,7 @@ function test_tutorial()
 	transactionDialog.selectFunction("setRating");
 	clickElement(transactionDialog, 200, 310);
 	ts.typeString("Titanic", transactionDialog);
-	clickElement(transactionDialog, 200, 350);
+	clickElement(transactionDialog, 200, 330);
 	ts.typeString("2", transactionDialog);
 	transactionDialog.acceptAndClose();
 	mainApplication.projectModel.stateDialog.acceptAndClose();