You can click on the 'Subbox' and then use this:

![enter image description here][1]

That will match everything as read.

To select every single email there, click on the checkbox on the top left then click the little 'popup':

![enter image description here][2]

Then mark everything as read. [1]: https://i.sstatic.net/VTpiM.png [2]: https://i.sstatic.net/FHi1U.png

You can click on the 'Subbox' and then use this:

That will match everything as read.

To select every single email there, click on the checkbox on the top left then click the little 'popup':

Then mark everything as read.