We just got a support request about Modified Sequence columns no longer supporting Contains, and I ran into this also. I found it very confusing. I just wanted to query for peptides containing M. So, I next tried the Peptides column (shows a link) and that also would not allow Contains M. Finally, I created a new report with Peptide Sequence and that worked.

We should support Contains on anything that looks like text.

Fix in rev 11883. We now support "contains", etc. on any column that is not "IFormattable". (This prevents us from doing "contains" on dates, numbers, etc. which is the right thing, I think.)