diff --git a/libweb3jsonrpc/WebThreeStubServerBase.h b/libweb3jsonrpc/WebThreeStubServerBase.h
index 168ab288a..451e2f9ee 100644
--- a/libweb3jsonrpc/WebThreeStubServerBase.h
+++ b/libweb3jsonrpc/WebThreeStubServerBase.h
@@ -121,7 +121,7 @@ public:
 	std::map<dev::Public, dev::Secret> const& ids() const { return m_ids; }
 
 protected:
-	virtual bool authenticate(dev::TransactionSkeleton const& _t) const;
+	virtual bool authenticate(dev::TransactionSkeleton const& _t) const = 0;
 
 protected:
 	virtual dev::eth::Interface* client() = 0;
diff --git a/mix/AppContext.cpp b/mix/AppContext.cpp
index 4bede3c49..4c8e61510 100644
--- a/mix/AppContext.cpp
+++ b/mix/AppContext.cpp
@@ -27,12 +27,11 @@
 #include <QQmlComponent>
 #include <QQmlContext>
 #include <QQmlApplicationEngine>
-#include <libwebthree/WebThree.h>
 #include "CodeModel.h"
 #include "FileIo.h"
 #include "ClientModel.h"
 #include "AppContext.h"
-
+#include <libwebthree/WebThree.h>
 
 using namespace dev;
 using namespace dev::eth;
diff --git a/mix/ClientModel.cpp b/mix/ClientModel.cpp
index 6859b0279..9a90d52e3 100644
--- a/mix/ClientModel.cpp
+++ b/mix/ClientModel.cpp
@@ -33,6 +33,7 @@
 #include "CodeModel.h"
 #include "ClientModel.h"
 
+using namespace dev;
 using namespace dev::eth;
 using namespace dev::mix;