After asking in the gnubg mailing list, I think that gnubg is not in a serviceable state when build with GTK3. The interface is broken, the board has problems too, you cannot do simple actions (e.g. comparing two moves at 4-ply).
I will copy what Philippe Michel (<[email protected]>) wrote. Il 06 agosto 2025 alle 21:23 Philippe Michel ha scritto: > The bug report seems to show that gnubg was built with GTK3: > ... > ii libgtk-3-0t64 3.24.49-3 > ... > > The GTK3 code in gnubg is fairly immature. There were some possibly > related fixes added recently (after 1.08.003 release), for instance: > > Author: Nikolas Nyby <[email protected]> > AuthorDate: Tue Jun 17 10:02:23 2025 -0400 > CommitDate: Fri Jun 20 20:26:51 2025 +0159 > > Improve drawing code for GTK 3 animation > > These changes fix flickering of selected pieces being dragged, using > the 2D board in GTK 3 (bug #65733). > > This is not necessarily what you experienced and there are other issues > anyway. > > At this time, from the point of view of gnubg, the practical solution > would be to build it with GTK2. > > I suppose it depends whether the Debian folks try hard to deprecate GTK2 > or if they just switched gnubg to GTK3 a bit casually, noticed that it > builds fine, but didn't test the resulting application much. Please rebuild with package with gtk2.
