Error when switching model types after data clearance prompt

[EskedarT]

Preliminary Checklist

• I have searched the existing issues list for similar reports and found none. If you did find a similar issue, please add a comment to the existing issue instead of opening a new one.
• I have verified that the issue exists in the latest version of DelftDashboard and its dependencies. Please update to the latest version and check if the issue still exists.

Severity Level

Medium

Steps to reproduce

The error can be reproduced in multiple ways. Here, you will see one of the ways. Assuming that you have been using the model builder to create a SFINCS model, now you would like to switch to the FIAT model builder.

To reproduce the error:

1. Use the model builder to create a SFINCS model.
2. Navigate to Files in the Menu bar and select New.
3. Confirm by clicking Yes to clear all existing data.
4. Now, go to Files again and select the new directory. You can choose a new directory to save files; please ensure the folder is empty.
5. Next, go to the Model Menu and choose FIAT.
6. The GUI will no longer display any model creation buttons, and you'll encounter the error: AttributeError: 'Toolbox' object has no attribute 'element'.

If you open the Model Menu again, you will notice that both FIAT and SFINCS models are selected.

Current behaviour

Desired behaviour

Allow users to switch between the two models seamlessly within the model builder interface without requiring a restart.
If a user opts to switch to the other model, they can be prompted to save their work. However, ensure that the GUI retains its functionality to create the model even after the switch.

Note that although there is already a pop-up window indicating that all existing data will be cleared when creating a new model, but switching the model type afterward triggers the error.

Additional context

No response