set WA_StyledBackground flag for custom Widget

from .constants import CONFIG_COMBOBOX_LONG, CONFIG_COMBOBOX_MIDEAN, CONFIG_COMBOBOX_SHORT

class Widget(QWidget):

    def __init__(self, *args, **kwargs) -> None:

        super().__init__(*args, **kwargs)

        self.style_option = QStyleOption()

        self.style_painter = QStylePainter()

        self.setAttribute(Qt.WidgetAttribute.WA_StyledBackground, True)

    # https://wiki.qt.io/How_to_Change_the_Background_Color_of_QWidget#Using_Style_Sheet

    def paintEvent(self, event):

        self.style_option.initFrom(self)

        self.style_painter.begin(self)

        self.style_painter.drawPrimitive(QStyle.PE_Widget, self.style_option)

        self.style_painter.end()

        super().paintEvent(event)

class FadeLabel(QLabel):

    def __init__(self, *args, **kwargs):

            self.gv.wheelEvent(event)

        return super().wheelEvent(event)

class SeparatorWidget(QFrame):

    def __init__(self, *args, **kwargs) -> None:

        super().__init__(*args, **kwargs)

        self.setFrameShape(QFrame.HLine)

        self.setFrameShadow(QFrame.Sunken)

class TaskProgressBar(Widget):

    def __init__(self, task_name: str, description: str = '', *args, **kwargs) -> None:

        super().__init__(*args, **kwargs)

        layout.addWidget(self.progressbar)

        self.updateProgress(0)

    def updateProgress(self, progress: int, msg: str = ''):

        self.progressbar.setValue(progress)

        if self.description:

        self.textlabel.setText(msg)

        self.progressbar.setValue(progress)

class FrameLessMessageBox(QMessageBox):

    def __init__(self, *args, **kwargs) -> None:

        super().__init__(*args, **kwargs)

        self.setWindowFlags(Qt.WindowType.FramelessWindowHint)

class ProgressMessageBox(QDialog):

    showed = pyqtSignal()

    def __init__(self, *args, **kwargs) -> None: