Enhance: allow more lists in menu if there is room for them

The GUI currently only allows for a limited number lists to be displayed. If there are any more in a domain, they are listed under the "Other lists" drop-down.

However plenty of screens these days have additional space to spare.
The code should allow for more lists.

Ideally the number would be automatically calculated, but allowing an option to override the default would be useful as an alternative.

Locate the GUI code that limits the number of lists and inspect how the "Other lists" drop-down is populated. Determine how available screen space and an optional override should affect the menu; the work is done when additional lists appear when space allows and overflow remains accessible.

Written by the indexing model from the issue text.