Quick search (suggestion): erasing all typed characters still displayed suggestions as if the 1st character is still typed

Steps to reproduce:

1. In the quick search (top right corner), type a word to start a suggestion search.
2. Erase all the typed characters.
   -> The field is still selected.
   -> Suggestions are still displayed as if the first letter of the word is still typed.

On previous versions it used to start suggestion from scratch, showing users in alphabetical order.