Create a new column for "Sort by Column" but cannot be found in the drop down list

Hello everyone

I currently encountered a strange situation: when I created a new conditional column (in the example I called it "Order_Category")  from Home -> Edit Queries after inputting a CSV file, the Order_Category column ONLY appeared in the filed with other columns but does NOT exist in the drop down list when I went to Modeling -> Sort by Column.

Below are some screen shots for your reference.

Since the dummy CSV file does not have the same issue but the really CSV file I generated from SPSS (file size is around 14 MB.) does, I am wondering that which step went wrong.

I do not think file size matters, but when I create CSV dummy files, they do not have the same issue.  

Thank you in advance!