SoapUI 5.3.0 lacks on MacBook Pro with macOS 10.12.5

SoapUI is terribly slow on my MacBook... For example, when i simply want to insert some chars into the username field of the authentication, it takes up to 20 seconds until it will be visible. The whole program often is completely frozen, but comes always back to live if i wait long enough.

Some times it is running normal, but it is very often terribly slow. I never had such experiences, as i was using soapUI on a windows computer.