Описание тега qtwidgets
Questions related to the QtWidgets module in Qt 5 that provides a set of UI elements to create classic desktop-style user interfaces.
The widget set of UI elements was put into its own module to keep Qt Gui modularized and less cluttered for GUI application using Qt Quick and so on.
The official documentation of this module can be found here.
Tagging recommendation:
You will often see questions tagged specifically as qtgui for QWidget, et cetera because the question is Qt 4 related even though it is about widget classes. From Qt 5 onwards, please try to use this tag for those cases. Make sure that you only tag questions with qtgui that contain questions about the core part of Qt Gui.