When having a NotifyChange("*") annotation around a method and a combobox in which the selectedItem is bound to a property, and that property changes to a null value, the combobox will continue showing the previous selected value instead of the null value.
If you use NotifyChange(

{"property1", "property2"}

) and list all the properties that change, the combobox behaves properly.
e.g.:

<combobox
id="bestellerCombobox"
autocomplete="true" constraint="strict, no empty"
model="@load(vm.personList)"
selectedItem="@bind(vm.selectedOrder.gastroblPerson)"
autodrop="true"
width="95%">
<template name="model" var="item">
<comboitem
label="@load(item) @converter('org.rorotec.lasso.converters.ConverterPerson')"
description="@load(item) @converter('org.rorotec.lasso.converters.ConverterPersonDetail')"/>
</template>
</combobox>

@NotifyChange("*")
@Command
public void filterItems()

Unknown macro: { orderList = // do some stuff selectedOrder = orderList.get(0); }

the above example doesn't work properly, while with
@NotifyChange(

{"selectedOrder", "orderList"}

) it works perfectly.