The Columns filter group in the Filter Pane of the Impact Analysis - DB tab consists of a checkbox list with search filter:
With this filter, you can limit the displayed BI data to the nodes which are stored in the selected database column(s).
Start typing a column name you are looking for in the search control, and the list will be limited to tables that contain your input.
There is an additional item (All) in the list of columns. Use it to toggle between all columns being selected and all columns being unselected.
If all columns are selected, or none of them, then the Columns filter is not applied, and it does not limit the data displayed.
See also