Question

Is it possible to render <optgroup> tags within select by native or ExtLib Combo box control?

I want to use native solution, so getComponent() or validators will work. That disqualifies inline html with jQuery/dojo, i think.

Answer 1

I have found this answer to my question.
Computed values for combo box in Domino Designer can return string vectors/arrays, usually as return value of @DbLookup or @DbColumn. While experimenting, I have found you can return native component for select items, including group (which inherits from select item).
Following snippet will build what I wanted: grouped hierarchy of items.

<?xml version="1.0" encoding="UTF-8"?>
<xp:view xmlns:xp="http://www.ibm.com/xsp/core">
    <xp:comboBox id="comboBox1" value="#{viewScope.combo}">
        <xp:selectItems>
            <xp:this.value><![CDATA[${javascript:var itms = new javax.faces.model.SelectItem[2];
var itm = null;
itm = new javax.faces.model.SelectItem();
itm.setLabel("label1");
itms[0] = itm;
itm = new javax.faces.model.SelectItem();
itm.setLabel("label2");
itms[1] = itm;

var g = new javax.faces.model.SelectItemGroup();
g.setLabel("Group");
g.setSelectItems(itms);
g
}]]></xp:this.value>
        </xp:selectItems>
    </xp:comboBox>
</xp:view>

Sample:

Based on this example you can combine many data sources to build computed <optgroup> combos, including backing beans or scoped variables.