Hi,
Kind of strange that MT supports IPv6, but winbox doesn’t?
Any plans to IPv6 enable winbox any time soon?
IPv6 works fine on winbox. What’s the problem?
Do not forget the brackets:
[myipv6address]
doh 
My baaad…
also, link local addresses can be used. If you see router in discover you will notice that it will look like this:
[link-local%interface-number]
for example:
[fe80::20c:42ff:fe73:403e%2]
for global addresses just square brackets.
for host names that resolves to ipv6 and ipv4, first will be used by default.