Thanks for reporting. So there is a real issue with version 0.8.0 and not only some unwanted debug message. And with gintro 0.7.7 it still works.
Unfortunately you are not able to provide a full small but complete example code, so it it not easy to find the cause of this error. Seems to be related with GtkTreeView widget, unfortunately one of the more difficult widgets. All our tests compile fine with v0.8.0 of course. From version 0.7.7 upto 0.8.0 much has happened, totally that was about 100 hours of work. If I remember correctly we did modify the connect macro a bit, can not remember details currently. Will try to investigate.
