In most places where selection is supported, shift-click will extend selection (select more items without deselecting the old) and ctrl-click (command-click on Mac) will toggle the selection of the clicked item.
In the data table, you can also clear row selection or column selection by clicking in the areas shown:
![danschikore_0-1676078207360.png danschikore_0-1676078207360.png](https://community.jmp.com/t5/image/serverpage/image-id/50024i789E944430F7D47B/image-size/medium?v=v2&px=400)