Undomanager did not remove graphics when undo()

Question

My attempted on using the UndoManager has been unsuccessful for a couple days and I'm stuck.

I did not setup a proxy.

I create a FeatureLayer object in memory with

var drawingPointLayer = new esri.layers.FeatureLayer(featureCollection, {
    id: "drawPointLayer",
    mode: esri.layers.FeatureLayer.MODE_ONDEMAND
});
mapApp.map.addLayer(drawingPointLayer);

created UndoManager and button to perfom undo redo actions

undoManager = new esri.UndoManager({maxOperations:50});

var undoButton = new dijit.form.ToggleButton({
    id: "undoButton",
    showLabel: false,
    iconClass: "dijitEditorIcon dijitEditorIconUndo",
    onClick: function(){ 
        undoManager.undo(); 
        checkUndoRedoState(); 

        mapApp.map.graphics.graphics.splice(mapApp.map.graphics.graphics.length-1, 1);
        mapApp.map.graphics.redraw();
        alert(undoManager.length + " | " + mapApp.map.graphics.graphics.length);
    }
}, "undoButton");
var redoButton = new dijit.form.Button({
    id: "redoButton",
    showLabel: false,
    iconClass: "dijitEditorIcon dijitEditorIconRedo",
    onClick: function(){ 
        undoManager.redo(); 
        checkUndoRedoState(); 
    }
}, "redoButton");

and add operation to UndoManager

function addToUndoManager(graphic, task){
    var operation;
    var featureLayer = mapApp.map.getLayer("drawPointLayer");
    //var featureLayer = mapApp.map.getLayer("landuseLayer");

    if(task=="add"){
        featureLayer.applyEdits([graphic], null, null, function() {
            operation = new esri.dijit.editing.Add({
                featureLayer: featureLayer,
                addedGraphic: graphic
            });
        });

    }

    if(operation)
        undoManager.add(operation);

    checkUndoRedoState();

    alert(undoManager.canUndo + " | " + undoManager.canRedo + " | " + operation.label + " | " + operation.type + " | " + undoManager.length + " | " + mapApp.map.graphics.graphics.length);
}

New point markers would be added to the map via mouse click. Undomananger would register. But when I press the undo button, the graphics on the map would not disappear.

I'm clueless on what to do next to solve this problem.

Please Help

Answer 1

I figure it out.. finally

what I should have done is use the addedGraphics parameter instead of addedGraphic

if(task=="add"){
    featureLayer.applyEdits([graphic], null, null, function() {
        operation = new esri.dijit.editing.Add({
            featureLayer: featureLayer,
            addedGraphics: [graphic]
        });
    });

}

I think this is a bug because when I read into the performUndo() code

alert(undoManager.peekUndo().performUndo) //not performUndo().. This will execute the function and won't display the inline code in alert

the alert shows

function(){ this._featureLayer.applyEdit(null, null, this._addedGraphics); }

when use addedGraphic: graphic

alert(undoManager.peekUndo()._addedGraphic);

returns undefined, which means that addedGraphic did not get pushed into _addedGraphics.