When it refuses to save
The three things Inkling will not let you do, and what each message means.
Inkling is fussy in three specific places. All three are protecting something.
A required field is empty
Fields with a red dot must have something in them. The message names the exact field, so you are not hunting. Fill it in and save again.
Something else is using this address
Two entries of the same kind cannot share a slug. Change one of them — the slug box sits under the title.
Something still points at this
You cannot delete a picture that a page is using, an entry that another entry links to, or a kind of content that another kind refers to. The message tells you what is holding on.
This is the single most useful no in the product: it is the difference between a tidy-up and a broken website.