The delete option is missing in custom subgrids of Opportunity Product in Opportunity form. It works only in the Inline view subgrid.

Repro:
Open any Opportunity > Click on the elipses (...) > Click on Form to customize it > scroll down to the Opportunity Products subgrid and doubleclick it to open the properties > Click on New and create new view > Click on Save and close > Select the view in the properties dropdown > Click Set > Click On Publish > Click on Save and Close.
Behaviour: The new form does not have the delete button to delete the products in the subgrid.
Expected Behaviour: The new form should have the delete button to delete the products in the subgrid.