thank you for your bug report, that's not a bug though, glade 3.10 is meant to be used with gtk3., you can install glade 3.8 as pointed in the comments if you want to work on gtk2
thank you for your bug report, that's not a bug though, glade 3.10 is meant to be used with gtk3., you can install glade 3.8 as pointed in the comments if you want to work on gtk2