Wisej 4.0.11 ToolBox missing in Visual Studio 2026

[itg-assistant]

Paul asked 2026-04-10 16:55:38 UTC

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

[itg-assistant]

Frank (ITG) answered 2026-04-11 19:52:09 UTC

Hi Paul,

most of this is under control of VisualStudio and beyond ours.
What I noticed is that once the Toolbox is working, leaving at least one designer file open seems to keep it working.

Best regards
Frank

[itg-assistant]

Paul answered 2026-04-16 18:11:42 UTC

Hi Frank, thanks for your response.

I removed Wisej 3 and Wisej 4 from Visual Studio 2026, then reinstalled only Wisej 4. The designer issue still occurs, but less frequently.

When it happens, I follow these steps:

• Close the project and Visual Studio

• Delete the

.obj

and

.vs

folders

• Reopen the project and rebuild

This refreshes the toolbox, so it works as a workaround.

Regards

[itg-assistant]

Alaa (ITG) answered 2026-04-16 18:20:27 UTC

Hi Paul,

Try clearing the Designer Cache.

That should help with the .NET Coredesigner toolbox not being loaded properly.

Best,
Alaa

[itg-assistant]

Paul answered 2026-04-20 16:13:27 UTC

Hi Ala, thanks for your suggestion.
For now, it doesn’t seem necessary.

Running “Clean All” in the rendering options, followed by Build → Clean, and deleting the .obj and .bin folders resolves the issue.

Best.