Do not try to move proof attempts to a non-existent prover (fix #553).
This commit also includes various aesthetic improvements to the dialog box.
Prochaines maintenances programmées: lundi 06/05, lundi 03/06, lundi 01/07
Pour plus d'informations: https://doc-si.inria.fr/display/SU/Gitlab
This commit also includes various aesthetic improvements to the dialog box.