Flickering custom titlebar

[Alundra]

Apparently the problem of flickering is because the widget created in the TitleBarWidget constructor doesn't use "this" as parent, using "this" the flickering is out but my layout is now not good visually, I have to find how recode it to be like before. I tried a QLinedEdit as titlebar and I saw the flickering was out, like that I found the answer.
EDIT:
SOLVED, but I need something tell me if that's correct. I have all widget using "this" as parent but the layout has no parent, then I use at the end "setLayout( Layout );".
setLayout set the layout to the new parent or a memory leak is present ?
EDIT:
Apparently the doc do like I do :
http://doc.qt.io/qt-5/qwidget.html#setLayout
All looks ok