You misunderstood, i meant that the programmers who designed Qt's layout systems expected the programmers who will use Qt would prefer to write code for laying out their UIs (most likely because this is what most UI libraries did and still do) so they designed the APIs with that in mind. I didn't mean that Qt required from them to do it via code.

This is in contrast to Lazarus' layout system, the programmers of which expected ("assumed", "thought", "believed", etc) that the programmers that will use Lazarus will create the UIs using the IDE's UI desiger and so made the layout system be more UI friendly as opposed to code-friendly.