Toolbox configuration in VS 2019 v16.3 for .NET Core 3.0 framework assemblies

Hi Support,

We are configuring our custom WinForms and WPF controls in VS 2019 toolbox by using a .pkgdef file with VSIX extension package installation. This is working for .NET Framework assemblies in 4.6 framework up to previous VS 2019 updates.

Working Example .pkgdef format in the VSIX:

[$RootKey$\ToolboxControlsInstaller\{Assembly_Name}, Version=X.X.X.X, Culture=neutral, PublicKeyToken=3d67ed1f87d44c89, processorArchitecture=MSIL] 
@="WPF 4.6-VS2019 Toolbox X.X.X.X"
"Codebase"="{Path\To\Assembly\4.6\FileName.dll}"
"WPFControls"="1"

Now we are trying the same method to configure the .NET Core 3.0 framework in VS 2019 v16.3 toolbox like below, but we couldn’t achieve this. Also manual drag and dropping the assembly in toolbox also not working.

[$RootKey$\ToolboxControlsInstaller\{Assembly_Name}, Version=X.X.X.X, Culture=neutral, PublicKeyToken=3d67ed1f87d44c89, processorArchitecture=MSIL] 
@="WPF netcoreapp3.0-VS2019 Toolbox X.X.X.X"
"Codebase"="{Path\To\Assembly\netcoreapp3.0\FileName.dll}"
"WPFControls"="1"

Could you please let us know is there something we could do to configure our controls in .NET Core 3.0 framework in VS 2019 update v16.3 version?

Note: We have updated the Visual Studio to 2019 v16.3 and also installed .NET Core 3.0 official update released in September 23rd, 2019.

Regards,
Balaji R

---

-ji