Make wheel scrolling transitive for widgets placed inside scroll areas

When a QSpinBox or QComboBox is placed inside a scroll area, the wheel scrolling inside the area is broken. Whenever the scrolling happens over outside of these widgets, the scroll area scrolls fine. However, during scrolling content of the area you may end up with a QSpinBox or QComboBox under your mouse pointer (even when you haven't moved it) - in this case further wheel scrolling is handled by the QSpinBox or QComboBox itself and doesn't scroll the parent scroll area anymore. This is annoying for the user, as he may have changed the current value of the QSpinBox or QComboBox unintentionally, and there is no easy way to bring the original value back again. The user is also forced to move his mouse pointer outside of these widgets in order to continue scrolling the area. This behavior is never wanted, unless the QSpinBox or QComboBox got a focus.

If it can't be fixed automatically, please consider adding a relevant property for the QWidget.

More info: In order to hack it inside QtCreator we have added Utils::setWheelScrollingWithoutFocusBlocked(QWidget *)¹ function.

¹: https://code.qt.io/cgit/qt-creator/qt-creator.git/tree/src/libs/utils/guiutils.cpp