close button into the glade-3 about dialog window

[anguila <anguila gmail com>]

I create a about dialog window with glade-3 in higher levels - about. And the about dialog it works but the close button doesn't do anything when I execute the program (doesn't close the widget/window).

The widget is a dialog-action-area but I can access to the close button because is a internal widget of glade.
Also after closing this window (at the first time) when I click again in the menu to show it again it doesn't shows, it appears a small gray square.

What I'm missing? 

Thx again!

anguila