XUL/Thunderbird: startEditing return

I'm playing with the thunderbird codebase, the aim being to implement inline contact editing. The current code catches the Click event on a XUL tree, and if it's a double click (events.detail == 2), it open the profile editor. I modified it so as to start editing the current treeCell, and I did add editable=true to the corresponding XUL document. The updated code reads

var orow = {}, ocolumn = {}, opart = {};
gAbResultsTree.treeBoxObject.getCellAt(event.clientX, event.clientY,
                                       orow, ocolumn, opart);

var row = orow.value, column = ocolumn.value.index;         
if (row == -1) 
  return;

if (event.detail == 2)
  gAbResultsTree.startEditing(row, column);

Unfortunately, when the code reaches the startEditing part, it returns

Error: uncaught exception: [Exception... "Component returned failure code: 0x80004001 (NS_ERROR_NOT_IMPLEMENTED) [nsITreeView.isEditable]" nsresult: "0x80004001 (NS_ERROR_NOT_IMPLEMENTED)" location: "JS frame :: chrome://global/content/bindings/tree.xml :: startEditing :: line 337" data: no]

I'm pretty much lost here. Could someone with more XUL experience help? Thanks!

I was trying to do something similar and I have same problem.

Wrapper with original abview set as __proto__ with functions overriden works fine until it is set as abResultsTree's view.

I've finally found (I hope) an elegant solution.

function MyAbView() {
    this.originalAbViewInstance = this.originalAbViewFactory.createInstance(null, Ci.nsIAbView);

    if (!this.proxiesGenerated) {
        // find out which interfaces are implemented by original instance, their property proxies will be generated later
        for (var ifName in Ci) {
            if (Ci[ifName] instanceof Ci.nsIJSID && this.originalAbViewInstance instanceof Ci[ifName]) {
                MyAbView.prototype.supportedInterfaces.push(Ci[ifName]);
            }
        }

        function generatePropertyProxy(name) {
            Object.defineProperty(MyAbView.prototype, name, {
                get: function() {
                    return this.originalAbViewInstance[name];
                },
                set: function(val) {
                    this.originalAbViewInstance[name] = val;
                },
                enumerable: true
            });
        }

        for (var prop in this.originalAbViewInstance) {
            if (this[prop] == undefined) {
                generatePropertyProxy(prop);
            }
        }

        MyAbView.prototype.proxiesGenerated = true;
    } else {
        for each (var interface in this.supportedInterfaces) {
            this.originalAbViewInstance.QueryInterface(interface);
        }
    }
}

MyAbView.prototype = {
    classID: null,

    _xpcom_factory: {
        createInstance: function(outer, iid) {
            return new MyAbView().QueryInterface(iid);
        }
    },

    QueryInterface: function(aIID) {
        for each (var interface in this.supportedInterfaces) {
            if (interface.equals(aIID)) {
                return this;
            }
        }

        throw Components.results.NS_ERROR_NO_INTERFACE;
    },

    originalAbViewFactory: null,
    originalAbViewInstance: null,

    proxiesGenerated: false,
    supportedInterfaces: [],

    // any overriden functions come here
};

It's implemented as a component to replace the original abview, but it might be modified to just create a wrapper.