// This works

[KSPAction(guiName = "Self Destruct", actionGroup = KSPActionGroup.Abort)]
public void startSelfDestruct(KSPActionParam param)
{
    // code
}



// this does not 

private string s_self_destruct = Localizer.GetStringByTag("#autoLOC_OCTO_RED_SELF_DESTRUCT");
[KSPAction(guiName = s_self_destruct, actionGroup = KSPActionGroup.Abort)]
public void startSelfDestruct(KSPActionParam param)
{
    // code
}