void set_destroy_with_parent(bool destroy
Sets whether or not the window should be destroyed with its transient
parent. If destroy is true, the
window will be destroyed when its transient parent is destroyed. If
destroy is false the window
will still exist after its transient parent is destroyed.
This method is most commonly used for dialog windows and sub-windows of
an application. If destroy is
true, the window will be closed when the user (or
application) closes the main window.