Comment 3 for bug 208260

No probs :-)

Not sure if it's worthwhile saying so here, but I suspect that the problem with gcalctool is because refresh_display() calls
ui_set_display(). However, ui_set_display calls:

        if (v->noparens == 0) {
            localize_number(localized, str);
            str = localized;
        }

Basically, it looks like it's trying to localize the whole expression, but this function is only build to localize an individual *number*. Thus is adds in the comma every 3rd character regardless...

Not sure how you'd get around this, but I think that's the problem here.