Hi,

Historically we always serialized the xalign property on check/radio buttons because those buttons left-align at runtime without modifying the GParamSpec which advertises the default value to be 0.5.

To work around this, we've now marked them deprecated as they are deprecated, and set them to "optional", so if you need to work with older versions of GTK+ and older glade files, Glade will still serialize the xalign property if you had set it to any value, while not serializing it at all by default.

Fixed with commit:

commit b413ac74daadbdc2bff5f9e708d04f067b57fafd
Author: Tristan Van Berkom <tristan.vanberkom@codethink.co.uk>
Date:   Fri Jan 29 11:31:34 2016 +0100

    Bug 750985 - GtkMisc property deprecations
    
      o Mark xalign/yalign/xpad/ypad as deprecated everywhere
    
      o Remove save-always for xalign
    
      o Make them all optional with optional default False, this
        has the side effect that if the property is set, it will
        be serialized in the output regardless of value, so we
        dont need the save-always anymore.
    
    We required save-always on xalign of some buttons because of bug 675042