[gtkmm] resize and get_size

["erwan ancel" <erwan ancel free fr>]

Hi,

I want to save window sizes to restore them at next usage. But when I do a
get_size() and resize() with the values obtained by the previous get_size(),
the window is 8 pixels less width and 34 pixels less height. I suppose it is
the window manager width and height borders. But I would expect that this
sequence wouldn't change the window size ...
Is this a bug or am I doing something wrong ?

    Erwan

nb: I use the windows ports of gtk/gtkmm.