allows to attach pop-up menu to the button
webix.ui({
view:"toolbar",
elements:[
{view:"button", label: 'Menu', popup:"my_pop"},
...
]
});
webix.ui({
view:"popup",
id:"my_pop",
body:{
view:"list"
}
}).hide();
The property's value is the ID of pop-up object that should appear on clicking the button. The object is initialized in the separate webix.ui() constructor. It's initially hidden.