Windows Form Designer can't handle custom components

Hi @...! 

Thank you for your request. What version of Rider do you use?

Could you please attach a sample code part or solution so we could double-check the issue on our side?

Thank you in advance! 

I am using the latest version Rider, 2021.1.3. The class in question is below.

- Steve

using System.Drawing;
using System.Windows.Forms;

namespace Form1
{
    /// <summary>
    ///     A ListView with DragDrop reordering.
    ///     <see cref="http://support.microsoft.com/kb/822483/en-us" />
    /// </summary>
    internal sealed class ListViewWithReordering : ListView
    {
        protected override void OnItemDrag(ItemDragEventArgs e)
        {
            base.OnItemDrag(e);
            //Begins a drag-and-drop operation in the ListView control.
            DoDragDrop(SelectedItems, DragDropEffects.Move);
        }

 protected override void OnDragEnter(DragEventArgs drgevent)
        {
            base.OnDragEnter(drgevent);
            var len = drgevent.Data.GetFormats().Length - 1;
            int i;
            for (i = 0; i <= len; i++) {
                if (drgevent.Data.GetFormats()[i].Equals("System.Windows.Forms.ListView+SelectedListViewItemCollection")) {
                    //The data from the drag source is moved to the target. 
                    drgevent.Effect = DragDropEffects.Move;
                }
            }
        }

        protected override void OnDragDrop(DragEventArgs drgevent)
        {
            base.OnDragDrop(drgevent);
            //Return if the items are not selected in the ListView control.
            if (SelectedItems.Count == 0) {
                return;
            }
            //Returns the location of the mouse pointer in the ListView control.
            var cp = PointToClient(new Point(drgevent.X, drgevent.Y));
            //Obtain the item that is located at the specified location of the mouse pointer.
            ListViewItem dragToItem = GetItemAt(cp.X, cp.Y);
            if (dragToItem == null) {
                return;
            }
            //Obtain the index of the item at the mouse pointer.
            var dragIndex = dragToItem.Index;
            ListViewItem[] sel = new ListViewItem[SelectedItems.Count];
            for (var i = 0; i <= SelectedItems.Count - 1; i++) {
                sel[i] = SelectedItems[i];
            }
            for (var i = 0; i < sel.GetLength(0); i++) {
                //Obtain the ListViewItem to be dragged to the target location.
                ListViewItem dragItem = sel[i];
                var itemIndex = dragIndex;
                if (itemIndex == dragItem.Index) {
                    return;
                }
                if (dragItem.Index < itemIndex) {
                    itemIndex++;
                } else {
                    itemIndex = dragIndex + i;
                }
                //Insert the item at the mouse pointer.
                ListViewItem insertItem = (ListViewItem) dragItem.Clone();
                Items.Insert(itemIndex, insertItem);
                //Removes the item from the initial location while 
                //the item is moved to the new location.
                Items.Remove(dragItem);
            }
        }
    }
}

At some point - not always - the same applies to User Controls.The Form Designer was unable to open, producing the same error. In VS I had no problem.

Hello @...! 

Please accept my apologies for the delay. 

Unfortunately, I was not able to reproduce the issue in my environment with a small test project. 

I'd like to ask you to try the latest EAP and check if the issue still persists. In this case, please, create a new issue with `Help | Report a bug` with automatically added logs so we could analyze them. 

Thank you in advance!