Many Logitech mice have a wheel that can either be free-spinning or "clicky". Some models even allow the application to control it, but some only allow the user to control it, either electronically or mechanically. There are a few situations in Qt in which it would be nice to know which mode the wheel is in; so maybe we could add a QInputDevice::Capability for this. E.g. a QComboBox should not allow spinning the wheel through the choices without opening the combobox, unless it's in "clicky" mode (or it's an unknown mouse, which is almost always going to be the "clicky" kind). A Flickable could scroll faster in "clicky" mode than in smooth mode (because in smooth mode, the events come much faster).

But I don't know if it's possible... especially cross-platform.