As several have indicated already, XXfrygatorXX and Steven Segal's Dad are confused by the fixed-limit (or spread-limit) rule. At $4/8, a $3 all-in bet will not reopen, and players who haven't already checked may complete to $8. A $4 all-in bet will reopen, and anyone may then raise to $12.
Quote:
Originally Posted by NOSUP4U
But in NL, it's double the raise I believe.
That's correct if it's an all-in first raise (not reraise).
But the general rule is, at least the amount of the previous bet or raise.
E.g.
A bets 50
B raises 75 more -> 125 to go
C calls 125
A reraises all in 80 more -> 205 to go
A has reraised more than the amount of the last raise (80 > 75). Despite A not making it 250 to go (twice 125), action is reopened and B may reraise at will.
==
Useless footnote: I think I read in a Ciaffone article in CP recently that this didn't use to be a standard rule, that many rooms would not reopen in this situation in bygone years. AFAIK what I wrote above is now the standard NL rule.