So many times I've been scratching my head wondering why the plugin I've just installed isn't working properly. Here are some possible reasons for unexpected behavior.
1. Your browser has cached the page.
Try a hard refresh, CTRL+F5, to make sure you're looking at a fresh page.
2. Hotaru is using cached database queries which are out of date.
Clearing the cache when you encounter problems remedies most problems. Just go to Admin -> Maintenance and click "Clear database cache" to instantly delete all the cached files.
You can disable or change the duration of the database cache in Admin - > Settings.
3. Hotaru is checking for plugin actions in the wrong order.
Depending on the order you install certain plugins, it's possible the resulting behavior might differ. Take for example the navigation bar. The Vote plugin adds "Top Stories" and "Latest" to the navigation bar and the Submit plugin adds "Submit a Story". The order those links appear in the navigation bar depends on the order you install those plugins. While that particular example won't break your website, more complicated plugin functions could cause unexpected results if fired in the wrong order.
The solution is simply to go to Admin -> Plugin Management and click the up and down arrows to change the order the actions are triggered in.