Parsing URL parameter in Vaadin application

I apologize for this very open question, but I did already lots of Research/test, and I can't figure out, so just thought that someone maybe already experimented the same behavior.

I have an URL as follow: http://localhost:8080/#!myapp/myparam=1234

I'm using the following just to check if my parameter is correctly passed:

    override enter(ViewChangeEvent event) {
        super.enter(event)
        println("PARAMETER MAP : " + event.parameterMap)
    }

With Chrome and Firefox, no Problem. With Internet Explorer (11), I need to refresh the page in order to see my param. By first load, i'm just having an empty map.

Should the parameter be passed/parsed differently for IE?

(I'm using Vaadin 8)