Items on canvas disappear after saving file with filechooser dialog

[Borja Mon Serrano <borjamonserrano gmail com>]

Hi all,

I'm developing an app to create hierarchical finite state machines for a
robot platform. For this app I need to save the automata designed in a xml
file, so I launch a filechooser dialog when the user picks in the "save"
button. Then, for saving the file, I iterate into the data structure to
save every property of each node and transition and it saves the file
correctly, but when the filechooser dialog closes, the canvas "hides" all
the items and I cannot see them (although I know they are already stored in
the data structure).

I tried to show all the items again (using its properties) and repaint the
canvas using update(), but nothing happened. Do you know what am I doing
wrong?

Thanks!

Borja.