Pleased to declare the FleetWnd segfault bug to be fixed

[Dilvish]

This was the bug which periodically caused shift-select operations on the FleetWindow to cause a crash;here is the commit. I decided not to open a PR on this one like I did the outpost combat bug, but I still wanted to make sure to point it out so it makes it into our next release notes bugfix list.

[Geoff the Medio]

This was the bug which periodically caused shift-select operations on the FleetWindow to cause a crash;

Is this the same as various drag-drop FleetWnd crashes?

viewtopic.php?f=25&t=9053
viewtopic.php?f=28&t=8845

[Dilvish]

Is this the same as various drag-drop FleetWnd crashes?

Possibly-- in both cases they had just selected multiple ships, and if that had been done via shift-select it's possible that it could have left one of the stored iterators in a bad state even if it didn't immediately cause a crash during the shift-select.

I looked through the ListBox code and the FleetWnd code for any more cases of the same kind of bug, and found what looks like at least a spots in ListBox that were at risk for the same bug. I put up a PR for some proposed additional safety checks.

[Vezzra]

If you really managed to nail that bug, that would be positively awesome. This nasty has been a pain for far too long.

[MatGB]

If you really managed to nail that bug, that would be positively awesome. This nasty has been a pain for far too long.

What he said, had it happen to me last week, couldn't replicate and logs weren't helpful.