hangs if showing multiple flash messages

[wi-wissen]

If I want to show multiple messages my website hangs (can't click anywhere. Opera and Edge and sometimes Firefox say that there is a script which solows the browser down).
I have to wait after messages are gone.

How to reproduce:

1. Setup like Readme
2. Call axios reguest and try to show an alle messages in response:

response.data.forEach(function(element) {
    flash(element, "success");
}); 

[wi-wissen]

Sorry, my mistake.
A Debugbar rendered very long SQL commands. I overlooked it.