JSException when switching activities quickly (C# input selected, Blazor Server)

[TahaSoydan]

Version

Elsa Server: 3.6.0
Elsa Studio (Blazor Server): 3.6.0
Hosting Model: Blazor Server

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Issue

When using Elsa Studio (Blazor Server), rapidly switching between activities causes a JavaScript exception if an activity contains an input configured with C# expression mode.

This results in:

Console errors (Monaco editor not found / disposed object issues)
Eventually, a visible error banner in the UI

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Steps to Reproduce

1. Open any workflow in the designer (Blazor Server hosting)
2. Select an activity that has at least one input
3. Switch that input's expression type to C#
4. Quickly click between different activities on the canvas
5. Observe errors in browser console and error banner on screen

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NOTE: The issue occurs specifically when an activity contains an input field with C# expression mode selected.

bandicam.2026-04-21.10-59-27-645.mp4