I traced this a bit further. It also happens if you click on the icons that let you place flags. This lead me to investigate the error message that gets printed on stdout to the effect that data/gfx/clearingflag cannot be found. Indeed, although the war and explore flag images are available in /usr/share/glob2/data/gfx (shouldn't that be /usr/share/games/glob2/...?), the clearing flag is not. But it is available in the source package, and if I rebuild the package from clean source, it's included in the resulting package.
Daniel
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