Comment 7 for bug 1672733

Ooh, I have a hunch. I got this segfault as the window was being closed. I suspect footprint_preview_panel.cpp:178 (GetEventHandler()) got an invalid object with a corrupt/nonsense vtable, sending it off to wxGenericImageList::~wxGenericImageList() instead of QueueEvent().

Proposed fix now is to make sure FOOTPRINT_PREVIEW_PANEL properly joins/stops the thread. This may be related to the warning on the waitMode parameter in http://docs.wxwidgets.org/3.1.0/classwx_thread.html#a40ef94232664185b4f1f8693eebeba86