Editor: Check book tool fails to check "#anchor" links
If a link consists only of a fragment identifier without a file name (e.g. "#anchor") the editor's "check book" tool will not report an error if the destination does not exist in the current file. If the file name is included (e.g. "foo.html#anchor"), the error is reported.
A minimal example which demonstrates this is attached.
Calibre version: 2.32
OS: Windows 7 & 8