высота хедера свернутой панели (технически, ширину)
webix.ui({
view:"accordion",
rows:[{
header:"panel 1",
headerAlt:"panel 1 (closed)",
headerAltHeight:22,
body:"content 1"
},
{
header:"panel 2",
headerAlt:"panel 2 (closed)",
headerAltHeight:24,
body:"content 2"
}]
});