Do not close the save tab when double cliking on a saved game

[captncavern]

In most of the games, when you are in the save tab and double clik on a save game, it means that you want to overwrite this game with the current one. In Xenonauts, it just close the save tab without doing anything --> many times, I think I have saved my game while in fact I just closed the save tab. I think many player will fall in this trap and that you should modify that.

Thx!