A column holds a number of rows. Each row comes in four main parts, not all of which are visible for all row values. Rows which represent classes have a pair or up/down arrows to the left of the row name button which you can use to control which parts of the row are visible.
If you double-left-click on the row name button, nip2 will pop up a viewer or dialog box for the value of the row. If you left-click, nip2 will select that row and deselect all other rows. If you click on an empty space in the workspace, it will deselect all rows. If you Ctrl-left-click, nip2 will toggle selection of that row. If you select one row and then Shift-left-click on another row in the same column it will select the second row and all the rows in between. If you drag with the left button, you can change the order of rows in a column. Hold down the right mouse button for a useful menu.
Alternatively, selecting View / Show Formula toggles the current column between displaying values for objects and displaying the formula.