Css not working on Layout cell (v6.3.1)

Suite and Optimus Suite 6
#1

In my layout I have a row defined like this:

        {
            id: "pToolbar",
            header: "Test Project ",
            css: "app_header"
        }

and then css like this:

.app_header {
    color: white;
    background-color:#0288d1;
    text-align:center;
}

the background color is set as expected but color text-align has no effect (I have tried several alignment properties)

#2

If you need to apply it to the header of the layout cell you need to use:

.app_header .dhx_layout-cell-header   {
	display:block;
	background-color:#0288d1;
	text-align:center;
}

.app_header .dhx_layout-cell-header__title{
	color: white;
}
#3

Thanks that works - please note that the docs do not say anything about what you mention above:

https://docs.dhtmlx.com/suite/layout__customization.html#stylinglayoutcells