Hi,
it seems that the FileDialog Node only evaluate itself by a pull from below (the window will only open if the the output-pin is connected to another evaluated node) (e.G. it will not work if you just connect the node to a sift(string) or a switch(string))
furthermore it would be really nice if the node would have an second output-pin which bangs as soon as the fileDialog is closed again (by open or cancel)
m.