Query Select

When I right click - I see “Query Select” - when I click on it - I get a white up and down arrow- side by side. What is this used for?
Thanks,

If you have multiple objects nested close together, the left mouse button will toggle select them one at a time when in the query select mode. Draw some nested circles and rectangles. With the up-down arrows inside the nest, click the left mouse button. (I just use the carving list to select whatever object I want when objects are nested close together.)

Thank you Bergerud!

All these years and I've never figured out what that was for, but I never tried real hard either I just select from the carving list too, but it could come in handy.