Resize grip is missing in PropertyGrid DropDown editor after update to net5.0-windows

• .NET Core Version: .Net 5 (net5.0-windows)

• Have you experienced this same bug with .NET Framework?: No

Problem description: I have simple drop-down editor IsDropDownResizable => true and GetEditStyle => UITypeEditorEditStyle.DropDown. For net472 or netcoreapp3.1 there’s resize grip under drop-down editor. After update to net5.0-windows resize grip is missing.

Expected behavior: Resize grip is displayed under editor control.

Minimal repro:

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            propertyGrid1.SelectedObject = new Foo(); // propertyGrid1 added via designer
        }
    }

    public sealed class Foo
    {
        [Editor(typeof(FooBarEditor), typeof(UITypeEditor))]
        public string Bar { get; set; }
    }

    public sealed class FooBarEditor : UITypeEditor
    {
        public override bool IsDropDownResizable => true;

        public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
            => UITypeEditorEditStyle.DropDown;

        public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
        {
            ((IWindowsFormsEditorService)provider.GetService(typeof(IWindowsFormsEditorService)))
                .DropDownControl(new Panel { BackColor = Color.Yellow });

            return value;
        }
    }

[willibrandon]

This issue appears to partially have something to do with the order in which the ResizeGripSize, ResizeBarSize, and ResizeBorderSize are being initialized in PropertyGridView.DropDownHolder.

If I change the order from this:

private readonly static int ResizeBarSize = ResizeGripSize + 1; // the thickness of the resize bar
private readonly static int ResizeBorderSize = ResizeBarSize / 2; // the thickness of the 2-way resize area along the outer edge of the resize bar
private readonly static int ResizeGripSize = SystemInformation.HorizontalScrollBarHeight; // the size of the 4-way resize grip at outermost corner of the resize bar

To this:

private readonly static int ResizeGripSize = SystemInformation.HorizontalScrollBarHeight; // The size of the 4-way resize grip at outermost corner of the resize bar.
private readonly static int ResizeBarSize = ResizeGripSize + 1;// The thickness of the resize bar.
private readonly static int ResizeBorderSize = ResizeBarSize / 2;// The thickness of the 2-way resize area along the outer edge of the resize bar.

The drop down resize bar is now displayed and can resize the drop down, but the resize bar is missing the resize grip.

I’ll try to figure out why the resize bar is missing the resize grip, any insight would be appreciated.

[kirsan31]

@ds1709

I also noticed that size of windows and controls is different in net472 and net5.0.

https://docs.microsoft.com/en-us/dotnet/core/compatibility/winforms#net-core-30