Hi @marijn. I am trying to implement indent/unindent too so I followed your advice. I added an indentation attribute to the node spec for paragraphs and it worked. When I hit Enter at the end of an indented paragraph though the new paragraph is not indented, that is it loses the attributes of the first paragraph. I fixed that by copying the splitBlock function and adding a few bits to it but overall it feels strange that the new paragraph does not keep the attributes of the one from which it was split.