The ‘Filter boxes max-height each’ value is not being honoured. The value used looks to be fixed to the default of 200px. I have tried values of 300px and 400px, as most of the taxonomies have 40+ terms. The width option is honoured.
In the attached image, the width is set to 300px, with the height to 400px. The number of displayed terms, is 7 terms for 200px, 300px, 400px. The height of the box corresponds to 200px.
That unfortunately does not apply to the selection container, it applies to the filter box container only (when used with checkboxes or other non-floating elements).
Luckily it is very easiely adjustable via a bit of custom CSS:
Where do I add the additional CSS? I tried under Appearance/Customise>Additional CSS with my child theme and it was not honoured. The only other obvious place seems to be Ajax Pro style.basic.css.php file in the plugin folder. Ideally I want to avoid that to ensure it does not get overwritten on the next update.