That’s 95% a feature and 5% a bug ....
95% feature:
This field is the „Quick search“, and of course it searches imediately while you are typing. Try it with the word „creation“ – type „c“ – wait – you will see that it jumps to first „c“ – type „r“ – it jumps to first „cr“ – type e – a- t-i-o-n – it will display the first(!) result of „creation“ (for next search result press F3) – type z – you will get a message that it can not find „creationz“
5% bug:
The message „...was not found“ appears twice.
For the entire search dialogue press „Ctrl+F“