Thank you for reporting this. We will not release any patches for 4.8.1, so you can either keep using this old version and use workarounds, switch to nightly build 4.9.x, or switch to new stable version 4.10 (due within a few days).
I am new to Slicer and currently using version 4.10.2. I also have a problem with the the apply button on the segmentation statistics module. It is not letting me select a segmentation for some reason. I have quit the programme and re-opened but it is still not working. What should I do? Screenshot 2020-06-30 at 11.41.31|690x360.