To update my previous post, I have been running another one of the "~akalla" 64-bit builds for Windows, this time from the [sort of] "beta channel" - a build of SM 2.38.
The good news is that the Windows taskbar weirdness mentioned above is now gone/fixed/whatever... the bad news is that the really unfortunate break in "restore-from-hibernate" behavior first noticed in the 2.35 "pre"
still-32-bit-build from Philip is still present and unfixed.
To sum up this last, now, unlike all pre-2.35 builds of SeaMonkey, I can no longer come back from a hibernate and have my periodic mail account checks still working... I am forced to shut down SeaMonkey all the way and restart it to get "auto" email account checks back - this brokenness is NOT tied to a 32 vs 64 -bit build issue.