Comment 19 for bug 1582687

For metacity you need install metacity-dbg package.

If you again have reproducible crashes with metacity it might be good idea to reproduce crash when running metacity with --sync commandline option:
metacity --sync --replace

sync option will ensure that stacktrace shows correct functon where it crashes:
ftp://www.x.org/pub/current/doc/libX11/libX11/libX11.html#Enabling_or_Disabling_Synchronization