I would like to draw attention to the following post which resulted in a "wontfix" and claim of "feature" by design:
Is this a problem, or is the GNAT Ada GTK toolset being upgraded to GTK 3?
The current GNOME/GTK maintainer policy of removal of a working glade for Ada seems not to be only about a "wishlist" item IMHO, as the removal of a GTK2 compatible designer renders an important part of the gtkada toolset completely inaccessible from Debian's package suite for Ada's GTK bindings.
Mention was already made in the post above (without examples though) of the need to continue providing the Glade GTK design tool in support of languages and tools that depend on the GTK2 libraries. The responses remind me uncomfortably of Microsoft around the dotnet launch: "dont care if we break your tools, bud" seems a poorly considered response and a poor advert for the stability of the development platform to [potential] users such as myself.
I would draw your attention to:
which clearly describes the reasons behind the 3.8.1 releases of GTK's Glade tool supporting GTK2 and 3, with 3.10.n supporting GTK3 only going forward - and shows how the two versions can co-exist to allow a smooth migration of dependant code over time. I read elsewhere that Ubuntu have already implemented packages to install the two side-by-side.
Another voice raises a similar question here:
I recall installing GNAT 3.1?p and the libgtkada package a long time ago, under SuSE, and the package depencies drew the appropriate version of the Glade GTK designer in automagically. Perhaps such a dependency should also exist in Debian for those languages' libraries such as gtkada etc. in Debian's package repository to help avoid such an oversight in future?
IMO It's important that the (3.8.1?) glade package as GTK2 designer should be available from the Debian packages for languages and toolsets that require it.
(FYI I read elsewhere that the 3.8.1 Glade requires GTK 2.24 (+?) as there's a build problem on lower versions of GTK).