WinForms Combo Box Flickering Issue

[LeafShi1]

.NET version

10.0

Did it work in .NET Framework?

No

Did it work in any of the earlier releases of .NET Core or .NET 5+?

No

Issue description

When the mouse moves over the combo box, an extra white box is drawn in the input area of ​​the combo box, resulting in a flickering effect.

Steps to reproduce

1. Create Winforms .NET app with ComboBox
2. Set comboBox1.FlatStyle = FlatStyle.Popup or comboBox1.FlatStyle = FlatStyle.Flat
3. Move the mouse over the combo box, a flickering effect occurs.

The original bug: https://devdiv.visualstudio.com/DevDiv/_workitems/edit/2053861