To reproduce the bug:
- edit the EditProduct form in applications/product/widget/catalog/ProductForms.xml
- add a new field with a hyperlink sub-element.
- refer to this new field in the first, non-collapsible field-group in the sort-order
- go to this page in the UI (edit a product in the catalog)
- the Expand All and Collapse All buttons do not work properly
It is not specific to the EditProduct form, but applies to any group of collapsible panes where one contains a hyperlink.
The attached patch simply checks that the li element actually exists.