When we create Interactive report and save it after deletion of Interactive Grid or page are reports saved somewhere or deleted forever.
I dont know if Oracle Apex saves reports after interactive grid is deleted,or Oracle Apex saves them somewhere.
I believe everything gets deleted.
For example, imagine it was page 1 which contained that interactive report (IR). You put some items onto it as well (so that you could filter data presented by the IR). You saved the page, used it for a while and then decided to delete it.
Once you're done, page number 1 is "free" to use and you can create a new page 1 - saving it, Apex won't say that "page 1 already exists" (somewhere). You can also name new items on page 1 with the same name as items on deleted page - no problem either.
Therefore, yes - I'd say that "Permanently delete" really means what it says.