I’m missing the information about Ignore Delete in the overview of the folders at the main screen. I suggest to add it to the Folder Type item of the folder (e.g. “Folder Type: Receive Only, Ignore Deletes”). Also putting this option into the Advanced tab of the Edit Folder dialog would be convenient.
Is there a good reason why Ignore Delete is hidden in the Advanced settings?
Related question: Does one device know how is the shared folder configured at another device? In particular, does one device know that the other device has the shared folder configured as Receive Only and Ignore Deletes? What folder metadata are exchanged between devices?