alx-tabs child not working

Hello,

I’m using Hueman 3.3.22 and i trying to fix the thumbnail size in the tab Popular Posts (alx-tabs.php) widget so i have duplicated it in my child theme and define a correct thumbnail size there is no effect. If i delete/rename alx-tabs.php in the parent folder, the alx-tabs.php in the child theme doesnt load and my website display a blank page.

I’m forced to apply my settings directly in the parent folder (works fine), how fix that ?

Thanks