Promoting to custom widget

[Lykurg]

What exactly does not work for you? What error do you get?

[Astronomy]

Hi,
so you have already done?:
A Container "QWidget myplaceholder" in your e.g. mainwindow.ui, which you had promoted to CYourNewClass?
Maybe you have missplaced or miss-set some setMainWidget( .. ) which will be shown over all other widgets?

in case: remove: setMainWidget( CYourNewClass-instance )

greetz A