Font awesome - some icons not available

is there any reason why some free font awesome icons are not availalbe via the SC IDE gui?

e.g.

<i class="fa-solid fa-chart-gantt"></i>

if i type the above text in a button label field, when i run the app the gantt icon is visible.

but if i try to add that icon via the “Font Awesome Icon” setting of the button, when i type “gantt” to search for it, no icon is found