Suitecrm 8.7 version when I added one button in editveiwdefs.php . it looks not working

when i try to add one button array(
‘customCode’ => ‘’,
), in public/legacy/modules/PM_PurchaseOrder/metadata/editveiwdefs.php it looks not working .
and also I try to edit it in public/legacy/custom/modules/PM_PurchaseOrder/metadata/editviewdefs.php
it also not working . So I am not sure the layout should use which one file to modify

This looks like a good approach. I will try it on SUITECRM7.14.
BTW 8.X versions are too slow.

My experience with v8 is that it’s fast.

Maybe it’s some configuration problem?