Qwt 6.4.1 not rendering in QtCreator

Hello All,

I have used qwt while back. Today I downloaded latest version 6.4.1. Let me assume that it must be something I am doing wrong :) before I report bug. I did read this thread https://www.qtcentre.org/threads/666...-custom-widget

I am playing around with latest qwt library. After building it and adding qwt plug-in to Qt Creator I can see qwt widgets in toolbar that I can dreg onto my canvas. Next I has issue promoting one of the Qwt widgets to my inherited class. Since this is no possible directly from Qt creator by promoting Qwt directly, I finally figured out that I created myplot.{h|cpp} in project folder and that I was able to promote.
What I am having problem is that my promoted QWidget to MyPlot (which is derived from one of the qwt widgets) not is invisible in designer. But when it runs I can see it. Al I doing something wrong? Am I missing some method in my MyPlot class that I have to call base qwt in order to see rendered widget in QtCreator designer on canvas? Is this some kind of limitation or Qt Creator?

All I am trying to do in my test app is integrate speedo_meter.cpp from qwt examples.