When playing on an ordinary survival world, I crafted some signs. Normally, these signs would be in my hand while having the slot active (Image 2 is from 1.7.9, the last version the signs are normal). As you can see by the first image, however, in the latest 1.8 snapshot as of June 25th, 2014, 14w26b, this visual is broken.
Related issues
duplicates
Attachments
Comments
migrated
[media][media]
migrated
This issue has been reported already. It has been linked to the original bugreport.
Please search before reporting any bugs, as it's likely that one exists already.