It would be really nice convenience thing to have QtCreator editor to automatically include the core classes when they are used and the include is missing. For example, if I add QPushButton the first time, I start typing QPus and look for it in the content assistant, but it's not there now. It would be good to have it there, even though it's not included yet. If I then choose it from the content assistant, the include for QPushButton would be added to the class.

Eclipse has this feature (at least for Java). It really helps you to keep focus and flow going.