Also, I've been struggling with GTK2 tree models and views, specially regarding to drag & drop. Of course, this is Grisbi related since we plan to improve user interface, which is still GTK1 based. Compare GTK1 version with the new version ... much better, heh?

I've never seen so complicated API and above all, all of this is undocumented regarding with GTK popularity. Even Tim-Philipp Müller's tutorial states "If you know anything about tree view drag'n'drop, you probably know more than the author of this text. Please give some feedback in that case." ... quite surprising !