Offer \@subfloatboxreset in subcaption package
Floating environments offer \@floatboxreset so it would be a good idea to offer \@subfloatboxreset (preset to nothing), too.
Edited by Axel Sommerfeldt
Floating environments offer \@floatboxreset so it would be a good idea to offer \@subfloatboxreset (preset to nothing), too.