when clearing an observablecollection, there equipment e.olditems

i have something here unequivocally throwing me off guard.

i have an observablecollection t filled items. i also have an eventuality handler trustworthy collectionchanged event.

when clear collection causes an collectionchanged eventuality e.action set notifycollectionchangedaction.reset. ok, that's normal. nonetheless uncanny conjunction e.olditems e.newitems anything it. i design e.olditems filled equipment private collection.

has anyone else seen this? so, have gotten around it?

some background: i am controlling collectionchanged eventuality insert detach another eventuality so i don't any equipment e.olditems ... i won't means detach event.

clarification:
i know support doesn't outright state act way. nonetheless each action, notifying me done. so, audacity tell me ... box clear/reset well.

below illustration formula wish imitate yourself. initial off xaml:

<window
    x:class="observablecollection.window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    title="window1"
    height="300"
    width="300"
>
    <stackpanel>
        <button x:name="addbutton" content="add" width="100" height="25" margin="10" click="addbutton_click"/>
        <button x:name="movebutton" content="move" width="100" height="25" margin="10" click="movebutton_click"/>
        <button x:name="removebutton" content="remove" width="100" height="25" margin="10" click="removebutton_click"/>
        <button x:name="replacebutton" content="replace" width="100" height="25" margin="10" click="replacebutton_click"/>
        <button x:name="resetbutton" content="reset" width="100" height="25" margin="10" click="resetbutton_click"/>
    </stackpanel>
</window>

next, formula behind:

using system;
using system.collections.generic;
using system.linq;
using system.text;
using system.windows;
using system.windows.controls;
using system.windows.data;
using system.windows.documents;
using system.windows.input;
using system.windows.media;
using system.windows.media.imaging;
using system.windows.navigation;
using system.windows.shapes;
using system.collections.objectmodel;

namespace observablecollection
{
    /// <summary>
    /// communication explanation window1.xaml
    /// </summary>
    open biased category window1 : window
    {
        open window1()
        {
            initializecomponent();
            _integerobservablecollection.collectionchanged += new system.collections.specialized.notifycollectionchangedeventhandler(_integerobservablecollection_collectionchanged);
        }

        private vacant _integerobservablecollection_collectionchanged(object sender, system.collections.specialized.notifycollectionchangedeventargs e)
        {
            switch (e.action)
            {
                box system.collections.specialized.notifycollectionchangedaction.add:
                    break;
                box system.collections.specialized.notifycollectionchangedaction.move:
                    break;
                box system.collections.specialized.notifycollectionchangedaction.remove:
                    break;
                box system.collections.specialized.notifycollectionchangedaction.replace:
                    break;
                box system.collections.specialized.notifycollectionchangedaction.reset:
                    break;
                default:
                    break;
            }
        }

        private vacant addbutton_click(object sender, routedeventargs e)
        {
            _integerobservablecollection.add(25);
        }

        private vacant movebutton_click(object sender, routedeventargs e)
        {
            _integerobservablecollection.move(0, 19);
        }

        private vacant removebutton_click(object sender, routedeventargs e)
        {
            _integerobservablecollection.removeat(0);
        }

        private vacant replacebutton_click(object sender, routedeventargs e)
        {
            _integerobservablecollection[0] = 50;
        }

        private vacant resetbutton_click(object sender, routedeventargs e)
        {
            _integerobservablecollection.clear();
        }

        private observablecollection<int> _integerobservablecollection = new observablecollection<int> { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 };
    }
}