Add the "search back for the nearest group of not less than/exactly N parallel blocks"

[Aleoami]

"And tell me how far back it is from the current one of the kind" Could be a nice instrument for "manually" investigating the DAG statistics and proving its params for being optimal or not :)

P.S. Also the same "how far from the current one of the kind" could be added to the red blocks search instrument as well. Probably just a momentarily floating hint.

P.P.S. Also then it's better to have both "search back" and "search ahead" options for both functionalities :) since I could be anywhere in the graph at a given time.