If no width and height are set the dialog size is automatic.
If we have for example a menu with a long list of elements the dialog occupy the whole terminal height and the backtitle covers the dialog header.
<img alt="whiptail_bug.png" src="/newt/issue/raw/files/b4247aca6685889fbd9680b5c49a7a3cc557be7f188af5d0330f8f5b790577cc-whiptail_bug.png" />
It would be nice if the height of the dialog took the backtitle into consideration and was 2 characters shorter.
to comment on this ticket.