Camera image regions widget is not fully drawn into its container in Stereo Camera Settings Dialog

[kheki4]

once the stereo camera is opened, this widget shows strange, partial rectangles, but not the expected sensor rectangle with the image ROI rectangle inside it. This problem occurs only in case of stereo camera, which suggests that the problem might be because this widget is already given meaningful image ROI and sensor size values upon creation in case of single camera, but in case of stereo camera, these values are only set when the actual cameras are opened using the Open button of the stereo camera settings dialog