real_layout = self.g.layout("fr", seed = self.g.vs['fr_seed_coords'])
plot.add(self.g, layout=real_layout, ...)
thanks, this works perfectly when resizing the window, when changing the size/weight threshold vertex are more stable but not completely fixed, that's probably impossible to achieve.
By the way, I checked your code related to the integration of PyGtk and igraph for graph plotting. Nice job! In fact, one of the reasons why I chose Cairo for plotting was that I knew that it can be integrated with GTK somehow, but I never had the time to figure out how to do it exactly, so thanks again!