This is how delete button shows up for me.
I created an Entity Permission with delete permission (in Portal Management) of the entity related to my form.
then in the Portal Editor, I checked "Enable Entity Permission" and toggle on the Delete option
And here is what I get
You need to assign a web roles as well for your entity permission (mine is only for Authorised User). if this still not working, there are some cases that Portal Editor is not updating properly, you can try to enable entity permission trhough Portal Management as well, but aside from that I have no clue why is it not working
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