The toolStripCombobox item's border does not render correctly for MenuStrip/ToolStrip contorl in NET11 mode

[Zheng-Li01]

.NET version

.NET 11.0.100-preview.7.26365.114 + Private dlls built from Net11/Integration-3 branch of https://github.com/KlausLoeffelmann/winforms repo

Did it work in .NET Framework?

Not tested/verified

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

Not support, new feature of #14768

Issue description

The toolStripCombobox item's border is not render well for MenuStrip/ToolStrip contorl in NET11 mode

Steps to reproduce

1. Create a WinForms application targeting .NET 11
2. Set VisualStylesMode = VisualStylesMode.Net11
3. Add a MenuStrip/ToolStrip control on the Form1.cs[Design] page
4. Add toolStripCombobox item for the menuStrip1/toolStrip1

[KlausLoeffelmann]

I am wondering, if we should prevent modern styles for the time being in the ToolStrip.
Let me think about that.