Mendix 5.15.1: this.mxform.domNode refers to empty mx-page

In Mx 5.13 I'm using a widget which is searching though the mx-page reached via a dojo.query within this.mxform.domNode. It seems that in 5.15 there is a substantial change because in 5.15 the mx-page is still found, and has mx-placeholder as child but when drilling down from there you'll find an empty childNodeList. It seems Mendix is rendering the page somewhere else now (not within the mx-page). So the question: how to reach the current page's DOM structure from widget perspective?
1 answers

I already found it.. There is a .mx-incubator div from Mendix 5.15. There you can find the Form dom structure while it's being built..