I would like to see this for every custom field type, users, threads, resources, media.
There's no guarantee the desired custom field id would be unused at the time of add-on install, so a conflict resolution system would be needed.
Whenever an empty value is supplied to a POSINT field, InputFilterer::cleanInternal converts it to a 1 instead of omitting it. NUM, UNUM, and FLOAT have the same problem in the appropriate setting when the value is out of range.
I understand it's clamping the values, but this is opaque and...
XenForo was spun off from ex-vBulletin developers and AFAIK bootstrapped. Discourse was VC-funded ($21M) and has hundred(s) of employees. And I'd wonder, even if XF did raise VC money, would they want the risk and headache of a big expansion.
It would only show in the overview if one or more resource fields are available in every category from both the resource field options and this add-on’s options. Also, are the parent categories selected too on both sides?
I meant that if you go to Resources > Resource Fields > (Field) > Applicable categories, is the category you are trying to view the widget in selected, and are the Filter widget positions "Resource category: Sidenav" and "Resource overview: Sidenav"?
The error message reveals why it's happening and it's all one problem. Found the problem and fixed it (v1.0.6 above), thank you for reporting it and for reporting these details.