Can not make a selection in a list box

[zagzebski]

I have a field "YTD" that I can not make a selection in (list box, table box, etc).  At first I thought it was possibly something to do with all the tables, variables I was loading in my script. So I loaded only the table with the field in it - but still I can not make a selection in the YTD field (it will temporarily flash the green selection then goes back).  I can make a selection in every other field from this table. How can this happen? I have never had this happen...

Calendar:
LOAD DateNum,
Date,
Key|Date,
UpdateDate_Calendar,
Year,
[Year Retention],
L3YearFlag,
Quarter,
Month,
TTMMonthToday,
Week,
Day,
DayName,
QtrYear,
MonthYear,
YearMonthCurrent_Flg,
[MonthYear(MMMYY)],
MonthYearNumber,
WeekYear,
MonthYearNumberSeq,
_YTD,
YTD,
TTM,
[Calendar Current Month],
_LM,
UpdateDate_WorkingDays,
[Working Days]
FROM
[..\SourceDocuments\QVD\Layer2\Calendar.qvd]
(qvd);

[zagzebski]

Thanks!