I've heard off-list from someone who uses gretl on Mac about a nasty
crashing bug, and I'm able to reproduce it. It seems to be (a) a GTK
bug and (b) triggered only on El Capitan.
To crash gretl: maximize a gretl window, then mouse up to the top of
the screen to reveal the window controls and press the close button.
The crash may not happen every time you do this, but in my experience
it happens pretty reliably if you try a few times. It may also be
possible to provoke the crash by using gretl in OS X's new Split View
mode. Apparently gretl is not the only program to suffer from this.
So, first, a word to the wise: to avoid data loss, it's best not to
maximize gretl windows on El Capitan. Since gretl is not designed to
run full-screen anyway that shouldn't be too much of a hardship.
As for a fix, I'm working on it but it's tricky. The problem seems to
lie in GdkQuartz, a component of GTK that's written in Objective C
using Apple APIs. Objective C is, to me, a strange language bearing
little resemblance to C, and I'm not at all familiar with the Apple
APIs. But I'm hoping we can piggy-back off work done by others who are
seeing this problem with their applications.
Allin