The game ran perfectly for a long time, then I got lots of screen lag... I saved the game, exited... restarted it and loaded the saved game. Still major lag in the screen action.
So I restarted my computer and loaded the saved game... still major lag. But when I loaded the same game earlier in time, it works fine again.
process 2592: arguments to dbus_connection_unref() were incorrect, assertion "connection->generation == _dbus_current_generation" failed in file ../../dbus/dbus-connection.c line 2822.
This is normally a bug in some application using the D-Bus library.