hello! i want to show a dialog when i double-click a row of a treeview, but the "gtk_tree_selection_get_selected" function fails in the callback, could anybody help me? Here are the functions: http://pastebin.ca/741016, "check_1" is showned but not "check_2" sorry... showned --> shown rafael: It looks like it should work. You could double-check by looking at the gtk-demo. murrayc: "You could double-check by looking at the gtk-demo" Sorry but I don't understand that. In the GTK+ tarball, there is a demo directory. It also has an example that responds to row activation. rafael: if that's actually the code, gtk_tree_view_get_selection() should go before the if() garnacho, it's true, I did it that way before, but the error occurred in the "gtk_tree_selection_get_selected" equally. rafael: you should be using the path argument of the row-activated callback, not check the selection you are absolutely right garnacho and probably not connect using swapped and use the right signal signature the error occurs in "gtk_tree_view_get_selection"