Wisej 4.0.11 ToolBox missing in Visual Studio 2026

Hi everyone,

I’ve been working with Wisej in a new project and I’m running into an issue that I can’t seem to resolve permanently.

Problem: Wisej controls keep disappearing from the Visual Studio Toolbox.

Environment:

• Wisej.NET: 4.0.11
• Wisej Designer: 4.0.11.1
• Visual Studio: 2026 latest version

I’ve already tried all the standard fixes:

• Clean / Rebuild solution
• Reset Toolbox
• Deleting .vs, bin, obj
• Clearing ComponentModelCache and Designer cache
• Restarting Visual Studio
• Opening forms in Design View
• Re-adding Wisej.Framework.dll manually

These steps do fix the issue temporarily, but after some time (often after reopening the solution or just continuing to work), the Wisej controls disappear again from the Toolbox.

I found this related post:
https://wisej.com/support/question/wisej-4-0-9-toolbox-missing-in-visual-studio-2026

But in my case, the suggested solutions are not enough since the problem keeps coming back.

At this point it feels like:

• Visual Studio is not persisting the Toolbox state correctly for Wisej controls, or
• There’s some incompatibility between the Wisej designer and VS 2026 Toolbox caching

Questions:

• Is this a known issue with Wisej 4 + Visual Studio 2026?
• Is there any more permanent fix or workaround?
• Any recommended setup to avoid the Toolbox resetting?

This is becoming a bit disruptive since I have to restore the Toolbox repeatedly during normal development.

Thanks in advance, Paul