if (ch == '\t')
if (ch == '\t' && tablen > 0)
	private int computeVisualLength(CharSequence seq) {		int size= 0;		int tablen= getVisualTabLengthPreference();				for (int i= 0; i < seq.length(); i++) {			char ch= seq.charAt(i);			if (ch == '\t')				size += tablen - size % tablen;			else				size++;		}		return size;	}