Failed to make horizontal Scroll Flow Panel

For applications run on mobile, Horizontal scrolled Flow Panel is very suitable.

I tried to use all CSS I found for the same subject in the forum as :

.anvil-role-flow-scroll-x .flow-panel-gutter {
flex-wrap: nowrap;
overflow-x: scroll;
}

but it does not work. Is there any update to it.

This is my app. link

The Flow Panel called : {Favorits_FP }in startup form .
for better execution example: choose the dropdown menus as : {Clothes - Women Clothes - T-Shirt}

Thank you for help

I couldn’t see the flow panel in the startup form.
I can only see a datagrid, is there something i’m missing?