This plugin is a great idea and something I really need. However, it doesn’t quite work… it seems to be skipping entries.
If I for example choose entry 1744, I would expect the previous entry to be 1742 and next 1753 – those are the previous and next entry in the WordPress post listing. I have edit privileges for both, as I’m the author of both.
Instead I get 849 as previous and 1801 as next. If I click myself to the previous entry, the next entry isn’t 1744, but 1599.
This is odd and makes this highly useful and necessary plugin unusable, which is a pity. This should really be a standard feature in WordPress.
Ok, figured it out. The problem is the way the query sorts the posts by post_date. If some entries have an older date but a bigger ID, it will mess the logic of this plugin. If I change the sort column to ID, then everything works as it should.
Version 1.5 of the plugin introduces the change you made manually: posts are now sorted by ID rather than post_date. There are filters in place to modify that behavior if someone likes to do things differently. The post navigation handling has been improved as well.