Describe the bug
When performing a batch fit (of either SANS or SESANS data type), the model can be selected, but it is not possible to select the option to fit with "polydispersity". The tick box is greyed out. This bug is present in v6.1.0 and v6.1.1. In v6.0.0, the option is available.

To Reproduce
Steps to reproduce the behavior:

1. Load multiple sets of data (any will do as long as there is more one, could be SANS or SESANS)
2. Tick "Batch mode" option and then Send to Fitting.
3. Select a category and model name.
4. See that the "polydispersity" option is not selectable.

Expected behavior
The option to select polydispersity should be selectable, even in Batch mode.

Screenshots
Version 6.1.1

Version 6.0.0

SasView version (please complete the following information):

• Version: present in 6.1.1 and 6.1.0 (tested) but not present in 6.0.0

Operating system (please complete the following information):

• OS: Windows 11

Installation method (please complete the following information):

• Installed: Windows installer

Additional context
Confirmed by Jeff Krzywon