No Yes No I don't know and I disagree with you. Editing visually is just one way to do it. It's not better or worse than doing it 100% in code. It's a matter of personal taste and skills. Some people need or like to use Designer while other can go perfectly well without it.

@Pl45m4 no but I don't know how to do that sizeHint() can return the right size in a layout.and I have a valid parent.

Hi Does the custom CustomQWidget do its own drawing with QPainter ?