如何让QScrollArea适配内部动态变化的QGridLayout正常显示？

我需要在QScrollArea里用QGridLayout创建多个QCheckBox，并且支持修改复选框的数量。目前遇到的问题是，当增加复选框数量时，这些控件会被强行压缩在QScrollArea的可视范围内，右侧并没有自动出现滚动条来显示超出的内容。

示例代码如下：

import sys
import numpy as np
from PyQt6.QtGui import *
from PyQt6.QtCore import *
from PyQt6.QtWidgets import *


class MainWindow(QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__()
        self.centralWidget = QWidget()
        self.setCentralWidget(self.centralWidget)
        self.mainHBOX = QVBoxLayout()

        layout_toApply = QGroupBox('Checkboxes')
        self.layout_toApply_V = QVBoxLayout()
        self.grid_toApply_V = QGridLayout()
        self.Stimulation_NbSources_Edit =QLineEdit('100')
        self.Stimulation_NbSources_PB =QPushButton('Apply')
        self.ChangeNBSource_fun()
        layout_toApply.setLayout(self.layout_toApply_V)
        self.layout_toApply_V.addLayout(self.grid_toApply_V)

        self.layout_toApply_V.addWidget(self.Stimulation_NbSources_Edit)
        self.layout_toApply_V.addWidget(self.Stimulation_NbSources_PB)

        self.mainHBOX.addWidget(layout_toApply)

        self.mainHBOX_W = QWidget()
        self.mainHBOX_W.setLayout(self.mainHBOX)


        self.widgetparam_w = QWidget()
        layout_toApplyparam_w = QHBoxLayout()
        self.widgetparam_w.setLayout(layout_toApplyparam_w)
        self.scrolltoparam_w = QScrollArea(self.widgetparam_w)
        self.scrolltoparam_w.setWidget(self.mainHBOX_W)

        self.mainlay = QHBoxLayout()
        self.mainlay.addWidget(self.scrolltoparam_w)



        self.centralWidget.setLayout(self.mainlay)
        self.centralWidget.setFixedSize(QSize(500,500))
        self.Stimulation_NbSources_PB.clicked.connect(self.ChangeNBSource_fun)


    def ChangeNBSource_fun(self):
        for i in reversed(range(self.grid_toApply_V.count())):
            widgetToRemove = self.grid_toApply_V.itemAt(i).widget()
            widgetToRemove.setParent(None)
            widgetToRemove.deleteLater()


        N = int(self.Stimulation_NbSources_Edit.text())
        nb_column = 10
        nb_line = int(np.ceil(N / nb_column))


        self.Apply_to_pop = []
        for l in np.arange(nb_line):
            for c in np.arange(nb_column):
                idx = (l) * nb_column + c + 1
                if idx <= N:
                    CB = QCheckBox(str(idx - 1))
                    CB.setFixedWidth(int(30))
                    CB.setChecked(False)
                    self.grid_toApply_V.addWidget(CB, l, c)
                    self.Apply_to_pop.append(CB)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec())

初始运行效果：

复选框数量翻倍后效果：

内容的提问来源于stack exchange，提问作者ymmx