如何在pyqt5中制作附加到QTabWidget的gap上的widget并进行相应的移动

from PyQt5.QtWidgets import QApplication, QMainWindow, QTabWidget, QLabel, QWidget, QVBoxLayout, QPushButton, QTabBar
from PyQt5.QtGui import QPainter, QColor
from PyQt5.QtCore import Qt

class AdditionalWidget(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        
        layout = QVBoxLayout()
        label = QLabel("Additional Widget")
        button = QPushButton("Button")
        layout.addWidget(label)
        layout.addWidget(button)
        self.setLayout(layout)

class CustomTabBar(QTabBar):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.additionalWidget = AdditionalWidget(self)
        self.additionalWidget.setGeometry(0, 0, 100, 50)
        self.additionalWidget.hide()
        
    def paintEvent(self, event):
        painter = QPainter(self)
        painter.setPen(Qt.NoPen)
        painter.setBrush(QColor(200, 200, 200))
        painter.drawRect(self.geometry())
        
        super().paintEvent(event)
        
    def mousePressEvent(self, event):
        if self.additionalWidget.geometry().contains(event.pos()):
            self.offset = event.pos()
        else:
            super().mousePressEvent(event)
        
    def mouseMoveEvent(self, event):
        if hasattr(self, 'offset'):
            self.additionalWidget.move(event.globalPos() - self.offset)
        else:
            super().mouseMoveEvent(event)
        
    def mouseReleaseEvent(self, event):
        if hasattr(self, 'offset'):
            del self.offset
        else:
            super().mouseReleaseEvent(event)

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        
        self.tabWidget = QTabWidget(self)
        self.setCentralWidget(self.tabWidget)
        
        customTabBar = CustomTabBar(self.tabWidget)
        self.tabWidget.setTabBar(customTabBar)
        
        self.tabWidget.addTab(QWidget(), "Tab 1")
        self.tabWidget.addTab(QWidget(), "Tab 2")
        
if __name__ == "__main__":
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()