src/Pure/Isar/outer_syntax.scala

       ((structure.span_depth, structure.after_span_depth) /: tokens) {
         case ((x, y), tok) =>
           if (tok.is_command) {
             if (tok.is_command_kind(keywords, Keyword.theory_goal)) (2, 1)
             else if (tok.is_command_kind(keywords, Keyword.theory)) (1, 0)
+            else if (tok.is_command_kind(keywords, Keyword.PRF_BLOCK == _)) (y + 2, y + 1)
+            else if (tok.is_command_kind(keywords, Keyword.QED_BLOCK == _)) (y + 1, y - 3)
             else if (tok.is_command_kind(keywords, Keyword.proof_open)) (y + 2, y + 1)
             else if (tok.is_command_kind(keywords, Keyword.proof_close)) (y + 1, y - 1)
             else if (tok.is_command_kind(keywords, Keyword.qed_global)) (1, 0)
             else (x, y)
           }