The selection buttons enable short-cuts to change the columns that will be included in the search results. 'Select Recommended' will choose a subset of the columns that MAST has defined as the most common and useful ones to include.  'Select All'  and 'Select None'  buttons will include all or none of the columns, respectively.  'Select None' followed by Choosing Output Columns can be used to customize the output columns when only a small number are desired.

Individual columns can be excluded from the search results using the close ('X') button associated with any column. To search for columns to include, click an empty area in the 'Output columns=' region and start typing. The text will be matched against all available column names and descriptions, and will be displayed at the top of the list. Available columns that do not match the search will be displayed at the bottom of the list. Clicking the checkbox next to a column adds the selected output column next to the existing columns. Using the 'Select None' or 'Select All' checkbox allows an alternative option to customize the output columns.