stylesheet.pro Example File
widgets/stylesheet/stylesheet.pro
  QT += widgets
  requires(qtConfig(combobox))
  HEADERS       = mainwindow.h \
                  stylesheeteditor.h
  FORMS         = mainwindow.ui \
                  stylesheeteditor.ui
  RESOURCES     = stylesheet.qrc
  SOURCES       = main.cpp \
                  mainwindow.cpp \
                  stylesheeteditor.cpp
  # install
  target.path = $$[QT_INSTALL_EXAMPLES]/widgets/widgets/stylesheet
  INSTALLS += target