Yeah, so I was trying to understand the example above and was wondering if you could, please, explain:

1) what is "l.",lower case L, seen together with "keyColumn" and "displayColumn"? and what are those two columns, configs of the store? I do not see them in the Ext's store, are they custom ones of the Labkey.ext.store?

2) what should be the correct expression for that example above? which div/tpl/anything else should be removed to make it correct?

am I correct to interpret that it should be this:

tpl:'<tpl for=".">' +
                                '<div class="x-combo-list-item">{[values["' +
                                this.keyColumn + '"]!==null ? values["' + this.displayColumn + '"] : "' +
                                (Ext.isDefined(this.lookupNullCaption) ? this.lookupNullCaption : '[other]') +'"]}' +
                                '</div>' +
                            '</tpl>',

if that's the case, then I almost understand, what it's doing, except for the bit in question 1)