def createElements(self):
        """
		Creates the widgets and docks of which the
		main window is composed.
		"""
        self.mainWindow = QMainWindow()
        projectController = ProjectController.Instance()
        self.transformTool = None

        # Render widgets
        self.fixedDataWidget = RenderWidget()
        self.movingDataWidget = RenderWidget()
        self.multiDataWidget = MultiRenderWidget()

        self.fixedRenderController = RenderController(self.fixedDataWidget,
                                                      "fixed")
        self.movingRenderController = RenderController(self.movingDataWidget,
                                                       "moving")
        self.multiRenderController = MultiRenderController(
            self.multiDataWidget)

        # Give references of the render controllers to the project controller
        projectController.fixedRenderController = self.fixedRenderController
        projectController.movingRenderController = self.movingRenderController
        projectController.multiRenderController = self.multiRenderController

        # Render properties widgets
        sizePolicy = QSizePolicy(QSizePolicy.Preferred, QSizePolicy.Preferred)
        sizePolicy.setHorizontalStretch(1)

        self.fixedPropWidget = RenderPropWidget(self.fixedRenderController,
                                                parent=self)
        self.fixedPropWidget.setSizePolicy(sizePolicy)
        self.fixedPropWidget.setFileChangedSignal(
            projectController.fixedFileChanged)
        self.fixedPropWidget.setLoadDataSlot(self.loadFixedDataSetFile)

        self.movingPropWidget = RenderPropWidget(self.movingRenderController,
                                                 parent=self)
        self.movingPropWidget.setSizePolicy(sizePolicy)
        self.movingPropWidget.setFileChangedSignal(
            projectController.movingFileChanged)
        self.movingPropWidget.setLoadDataSlot(self.loadMovingDataSetFile)

        self.multiPropWidget = MultiRenderPropWidget(
            self.multiRenderController, parent=self)
        self.multiPropWidget.setSizePolicy(sizePolicy)

        self.verticalSplitter = QSplitter()
        self.verticalSplitter.setOrientation(Qt.Vertical)

        # Create the layouts

        fixedDataTitleWidget = TitleWidget("Fixed volume")
        multiDataTitleWidget = TitleWidget("Fixed + Moving")
        movingDataTitleWidget = TitleWidget("Moving volume")

        fixedLayout = QGridLayout()
        fixedLayout.setSpacing(0)
        fixedLayout.setContentsMargins(0, 0, 0, 0)
        fixedLayout.addWidget(fixedDataTitleWidget)
        fixedLayout.addWidget(self.fixedDataWidget)
        fixedWidget = QWidget()
        fixedWidget.setLayout(fixedLayout)

        multiLayout = QGridLayout()
        multiLayout.setSpacing(0)
        multiLayout.setContentsMargins(0, 0, 0, 0)
        multiLayout.addWidget(multiDataTitleWidget)
        multiLayout.addWidget(self.multiDataWidget)
        multiWidget = QWidget()
        multiWidget.setLayout(multiLayout)

        movingLayout = QGridLayout()
        movingLayout.setSpacing(0)
        movingLayout.setContentsMargins(0, 0, 0, 0)
        movingLayout.addWidget(movingDataTitleWidget)
        movingLayout.addWidget(self.movingDataWidget)
        movingWidget = QWidget()
        movingWidget.setLayout(movingLayout)

        horizontalSplitter = QSplitter()
        horizontalSplitter.setOrientation(Qt.Horizontal)
        horizontalSplitter.addWidget(fixedWidget)
        horizontalSplitter.addWidget(multiWidget)
        horizontalSplitter.addWidget(movingWidget)

        propsLayout = QHBoxLayout()
        propsLayout.setSpacing(1)
        propsLayout.setContentsMargins(0, 0, 0, 0)
        propsLayout.addWidget(self.fixedPropWidget)
        propsLayout.addWidget(self.multiPropWidget)
        propsLayout.addWidget(self.movingPropWidget)

        propsWidget = QWidget()
        propsWidget.setMinimumHeight(245)
        propsWidget.setMaximumHeight(350)
        propsWidget.setLayout(propsLayout)

        self.verticalSplitter.addWidget(horizontalSplitter)
        self.verticalSplitter.addWidget(propsWidget)
        self.verticalSplitter.setStretchFactor(0, 2)
        self.verticalSplitter.setStretchFactor(1, 1)
        self.setCentralWidget(self.verticalSplitter)