Fix for AOOB in MeasuredText

            for (int i = 0; i < spans.length; i++) {

                int startInPara = spanned.getSpanStart(spans[i]) - start;

                int endInPara = spanned.getSpanEnd(spans[i]) - start;

                // The span interval may be larger and must be restricted to [start, end[

                if (startInPara < 0) startInPara = 0;

                if (endInPara > len) endInPara = len;

                for (int j = startInPara; j < endInPara; j++) {

                    mChars[j] = '\uFFFC';

                }