seems like there is no support for withCount

[Cipa]

works
$dataTable = new LiveControl\EloquentDataTable\DataTable($courses->with('outline')->with('outlines'), [ 'name', 'code', 'id']);
$course->name . ' (' . $course->code . ')' . $course->outlines->count(),

doesn't work
$dataTable = new LiveControl\EloquentDataTable\DataTable($courses->with('outline')->withCount('outlines'), [ 'name', 'code', 'id']);
$course->name . ' (' . $course->code . ')' . $course->outlines_count,

Thank you