Bug in Select tool

Hi Team,

I am using Alteryx version 11.5. Today, I noticed that the Select tool is not showing me checkboxes in the left column which are used to filter the columns.  I used input tool to import a csv file into the Alteryx. Then used Select tool. The select tool shows me all the columns but does not show any checkboxes. Is it some sort of bug? 

I have attached a screenshot. 

Thanks