Scenario where DesignMode is false from the NET WinForms OOP designer

[tracktownsoftware]

Description

When using my NET6 Windows Forms custom control to display a dialog at design time, the DesignMode value is incorrectly false even though it is running in the DesignToolsServer process.

Reproduction Steps

My github sample to reproduce:
https://github.com/tracktownsoftware/MicrosoftWinFormsDesignerSDK_DesignModeBug

The above repository includes a Nuget package you can use to test and reproduce. The nuget package contains a custom NET6 WinForms "MyButton" control with WinForms Designer Extensibility SDK design-time support.

Expected behavior

DesignMode should be true because it is running in the DesignToolsServer process.

Actual behavior

DesignMode is false.

See https://github.com/tracktownsoftware/MicrosoftWinFormsDesignerSDK_DesignModeBug/blob/main/README.md

Regression?

No response

Known Workarounds

Rather than using DesignMode check for System.Diagnostics.Process.GetCurrentProcess().ProcessName=="DesignToolsServer"

Configuration

No response

Other information

No response

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.