Getting this error when clearing and readding items to a ListBox "An anchor control must be a visual descendent of the ScrollContentPresenter"

[Leopard20]

I'm trying to implement a custom search feature for my ListBox. The way I currently do this is:

1. I have a TextBox control called searchBox with a TextChanged event. The listbox is called list:
2. When I first populate the listbox, I also store all listbox items in a separate List

 list.Items.Clear();
 allProcessItems.Clear();
 foreach (var (icon, name, id) in processes)
 {
     var item = new ProcessItem(icon, name, id);
     list.Items.Add(item);
     allProcessItems.Add(item);
 }

3. This is what I do when text changes:

private void SearchBox_TextChanged(object sender, TextChangedEventArgs e)
{
    IEnumerable<ProcessItem> items = null;

    if (searchBox.TextLength == 0) // when empty, show all items
    {
        items = allProcessItems;
    }
    else // only show matches
    {
        items = Search.Find(searchBox.Text, allProcessItems).Select(_ => (ProcessItem)_);
    }

    list.Items.Clear();
    foreach (var item in items)
    {
        list.Items.Add(item);
    }
}

But then I get a crash in Main saying An anchor control must be a visual descendent of the ScrollContentPresenter.
Can anyone please tell me if I'm doing something wrong or if this is a bug?

[Leopard20]

I found a workaround. Previously, ProcessItem was derived from ListboxItem (public class ProcessItem : ListboxItem)
This time I just decided to rearrange stuff and make it the content of a ListboxItem:

list.Items.Clear();
allProcessItems.Clear();
foreach (var (icon, name, id) in processes)
{
   var item = new ProcessItem(icon, name, id);
   list.Items.Add(new ListBoxItem() { Content = item });
   allProcessItems.Add(item);
}

(I also had to change the search fnc but that's not really important)

Still, I'm still wondering if this was indeed a bug and if so should I report it.