diff --git a/carbox2d.pro b/carbox2d.pro
index 2696e4c..c230c85 100755
--- a/carbox2d.pro
+++ b/carbox2d.pro
@@ -1,5 +1,5 @@
 TEMPLATE      = app
-QT  += opengl
+QT  += widgets opengl
 HEADERS       = \
     world.h \
     track.h \
diff --git a/mainwindow.cpp b/mainwindow.cpp
index 55093e0..daaace7 100755
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -9,8 +9,8 @@ MainWindow::MainWindow(QWidget *parent) :
     connect(world, SIGNAL(creteNewCar()), render, SLOT(createCarCallList()));
     connect(world, SIGNAL(freeCallListNumber(uint)), render,
             SLOT(deleteCallList(uint)));
-    this->setCentralWidget(render);
-    this->resize(800, 600);
+    setCentralWidget(render);
+    resize(800, 600);
     setWindowTitle(tr("Carbox2d"));
     createMenu();
     speed = SPEED_NORMAL;
@@ -96,7 +96,7 @@ void MainWindow::setSpeed(int newSpeed) {
 
 void MainWindow::showAbout() {
     QMessageBox::about(this, tr("About carbox2d"),
-                       tr("<h2>Carbox2d 0.2.2</h2>"
+                       tr("<h2>Carbox2d 0.2.3</h2>"
                           "<p>Evolution simulator like "
                           "<a href='http://boxcar2d.com/'>http://boxcar2d.com/</a></p>"
                           "<p>Copyright &copy; 2012 Zagidulin Artyom</p>"
diff --git a/mainwindow.h b/mainwindow.h
index 44989ef..960e4df 100755
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -1,7 +1,7 @@
 #ifndef MAINWINDOW_H
 #define MAINWINDOW_H
 
-#include <QtGui>
+#include <QtWidgets>
 
 #include "render.h"
 #include "world.h"
@@ -9,7 +9,7 @@
 class MainWindow : public QMainWindow {
     Q_OBJECT
 public:
-    explicit MainWindow(QWidget *parent = 0);
+    MainWindow(QWidget *parent = 0);
     ~MainWindow();
 
 signals: