V2.39c - editing %_folderpath% in file list

Though Customise columns... "Field:" (sic) accepts %_folderpath%, the resultant column does not allow editing. Other pseudofields edit fine e.g. %_filename_ext%.

Is %_folderpath% edit blocked for some reason? If so, is there a workaround? It would be really useful to have it editable like the others.

Anyone, please?