Related to T62882
When the SupportsMapping modifier flag was added 3fab39f to the dynamic paint modifier it was added commented out. It may have not worked back then, but it seems to work fine now.
MOD_weightvgedit.c was updated similarly in 2c5a919
Interestingly all of the weight editing modifiers (MOD_weightvgmix.c MOD_weightvgproximity.c MOD_weightvg_util.c) also have the eModifierTypeFlag_SupportsEditmode tag as well, even though toggling the option in the UI doesn't do anything in edit mode (The modifier always affects edit mode.) I am wondering if I should add the same tag to MOD_dynamicpaint.c so that it behaves in the same way.