i do not know since when(cwicy do not have this before),
when duplicate p block, it will automatic generate css class on every p, when dumplate 10 times, it will have 10 class here.
when duplate one p in many times, it need hundreds times to remove each class name on every p ,
seems this it not very good solution here( this happen not only p block, seem on all the block)
so kindly report it here for reference.