This information applies to version(s): Last version
For DxO PureRAW 2.5 and version DxO PhotoLab 6.2, and all previous versions, when using the distortion correction, the corners of the resulting images were slightly cropped, resulting in the maximum rectangular image area.
Beginning with PureRAW 3 and DxO PhotoLab 6.3 it is possible to gather all of the images projected by your lens. This results in black areas, which are not part of the image and could at first sight be misunderstood as distortion. However, this is just the outer shape of the image, whereas lines as part of your scene will be perfectly straight.
For distortion correction cropping, there are three options to choose from for each image/batch of images.