Comment 1 for bug 1659446

Application windows like dialogs rendered underneath the Dock on OS X is a toolkit issue (GTK+, happens with both available backends (X11, Quartz), and with GTK2 as well as GTK3), not specific to Inkscape (AFAIU this can't be changed within the project itself).

The dialog of the mentioned is rather long (high), which poses general accessibility issues for users with small screens (or with larger UI font sizes and other theme settings like spacing and padding), not only on OS X.

Possibly the options could be split into two tabs, as demonstrated in attached screenshot.