Portal Rows can be deleted even when allow deletion of portal row is turned off for the portal
Operating system version
Mac and Windows
Steps to reproduce the problem
1. have a layout with a portal
2. have a field in the portal that is button (script attached to the button can do anything or be an empty script - script content not important to reproducing issue)
3. click into a field to put the parent record into edit mode
4. press and hold the delete button (backspace button if you are on a PC)
5. while holding down the delete button click on the button in the portal row
6. A dialog box will pop up saying "delete this one related record"
7. click okay
Portal row deletion should be disallowed since we didn't check the checkbox to allow deletion of portal rows through the portal.
you just deleted the related portal row even though that portal was set to not allow deletion of records through that portal.
The only work around that I have found would be to modify the privilege set to disallow deletion of records in the associated table (this should not be necessary, but ends up being necessary due to the behavior allowed by the reproducible steps above)