A few months ago - actually somewhat more than half a year - we had a guy called "Misak" join the #seamonkey
channel, asking if SeaMonkey would have a session restore feature that would bring back your tabs after a crash or restart of the suite. We didn't have that implemented, back in typical open source manner told him we'd be happy if someone (he?) would port the code that already does that from Firefox to SeaMonkey, as it should be fairly compatible. His rely was that it's been quite some time that he did programming work and he was unfamiliar with Mozilla code, but he'd be willing to try doing that work.
On May 4th, 2008, Misak Khachatryan had made the first step and attached a first patch
to the 5-digit bug that had been open for that suite feature for 8 years before that already. It took a number of additional iterations, integration with SeaMonkey's different restore-closed-tab implementation, almost 100 more bug comments, long waits for reviews from busy-with-real-life community members (sorry!), another bug for porting more work
on top of that (the Firefox code is somewhat of a moving target as well) and all in all about 7 months - but:
SeaMonkey session restore has landed a few hours ago!
There are still a number of followup issues to fix, like a test leak
caused by this landing, ported tests for the feature itself, fixups/improvements to the ported code, and original SeaMonkey twists like restoring more than just browser windows and tabs, all of which can be worked out by Misak and anyone else who wants to help us there, step by step. Still, it looks like SeaMonkey 2 Alpha 3 and later will ship with this new feature - and everyone can profit from one guy "scratching his itch", so to speak.
Thanks to Misak for doing this work - and to everyone who also is not familiar with our code yet but knows something (s)he'd like to see fixed: Take this guy as a model and try to make what you'd like a reality - we're surely happy to help you get on your way and get your code into our tree!