Occasionally (haven't found a pattern), when I enter text into the "Serves line" field (i.e. when I give a name to a line), there appear random characters (e.g. I type an 'a' and there appears a 'p') and also repeating characters such as ca. 50 times the letter 'o' without me pressing any key. This does not happen with any other program on that computer.
I am running simutrans pak64 111.2.2, debian linux with awesome window manager.