Line 10b, charitable deduction when you don't itemize

[tdattomo]

I am preparing a return for my retired mother.  She is filing single 

She only has social security and a pension 1099-R. 

I entered her charitable contributions at $350, but the program only brings over $150.00.  I can't find a limit for a single filer that might lower her amount to 150.00  That limit seems to apply to the head of household status and not for single or married

Is this a program bug or some limit that I don't know about?

[PattiF]

People who are Married Filing Separately are only eligible for a deduction of $150. If that is not her situation, she should be eligible for the $300 deduction.