I don't know if anyone else had the problem, but several times I have commited the error to mark all my mails like read in the Pipedrive inbox.
As many, the knonw read mails are the ones for me I have not answered, so that brings me a lot of trouble.
The design of the "mark all mails as read" buttom doesn't help a lot, as its easy to clic on "mark" instead "Filter" and select the first option without looking on it slowly.
It would be better to make some extra step like: Are you sure to mark all mail as read or quit the option of mark as long as you do not have selected any mail.