The DICOMSeriesReader stores all DICOM-Tags of the DICOM images as StringProperties on both the DataNode and the Image itself.
The ImageVtkMapper2D searches these Properties for the desired default Level/Window values as they are defined in the DICOM-Tags and uses them to display the image.
However, these values are not set using the 'force-flag' of the mitkLevelWindow::SetLevelWindow() method. Thus, the desired level/window values will not be applied correctly if they are out of the default bounds.
Setting the 'force-flag' to true would make sure the Level/Window values that are defined in the DICOM-Tags are actually used.