Kernel set to 'None' was incorrectly displayed as 'default'. fixes QubesOS/qubes-issues#4043
@@ -60,6 +60,8 @@ def prepare_choice(widget, holder, propname, choice, default,
oldvalue = qubesadmin.DEFAULT
else:
oldvalue = getattr(holder, propname)
+ if oldvalue == '':
+ oldvalue = None
if transform is not None and oldvalue is not None:
oldvalue = transform(oldvalue)