There is currently a working group trying to figure out how to improve form errors in Drupal core. This includes inline form errors. If you are interested in the discussion and want to help out checkout the following threads:
What is IFE
IFE or Inline Form Errors allows you to place form submission error inline with the form elements. Three options are provided for setting your inline error behaviour. You can configure the default behaviour or override the behaviour on a per form basis. You can add as many forms as you like.
IFE provides three behaviours for the configured forms
- Leave the messages in place, this option will copy the error messages and place them inline. The original error messages set by Drupal will remain in place
- Show an alternative message, this option will replace the original messages with a generic error message such as 'Please correct all errors.'. This message can be set in the IFE configuration page. The original error messages are placed inline with the form elements
- Remove all messages, this option will remove all error messages and place them inline with the form element
In all cases only the messages related to the form will be touched. All other messages will remain in tact.
There is only so much the Drupal FAPI allows us to do. We now have a decent generic codebase for the D7 of IFE wich will catch most of your error needs. But some modules have some special tricks, that is where it gets a bit more complicated.
We tested a lot of stuff, but can't test everything so help us out with finding those special cases so we can tweak the error processing or add workarounds if needed.