Duplicate case label : IDE Bug?

Hello,

I am experiencing a "Duplicate case Label" using this code in a win-1252 codepage :

        for (int cnt = 0; cnt < nrOfChars; cnt++) {
            ch = someText.toLowerCase().charAt(cnt);
            switch (ch) {
                case 'ä':
                    res.append("AE");
                    break;
                case 'ö':
                    res.append("OE");
                    break;
                case 'ü':
                    res.append("UE");
                    break;
                default:
                    res.append(ch);
                    break;
            }
        }

This appears to me like an bug, the prior version of the code also threw this error :

        for (int cnt = 0; cnt < nrOfChars; cnt++) {
            ch = someText.charAt(cnt);
            switch (ch) {
                case 'Ä':
                    res.append("AE");
                case 'ä':
                    res.append("AE");
                    break;
                case 'Ö':
                    res.append("OE");
                    break;
                case 'ö':
                    res.append("OE");
                    break;
                case 'Ü':
                    res.append("UE");
                    break;
                case 'ü':
                    res.append("UE");
                    break;
                default:
                    res.append(ch);
                    break;
            }
        }

Thanks in advance!

regards,

Marcus