[Python] Poor responsiveness of a QScrollBar handle [duplicate]

Not sure what is the issue: I am using list view and I struggle with the scrollbar. Somehow, the handle part is not always responsive. Sometimes I can click the handle and scroll fast to the place which I need, sometimes I cannot. I made a MRE from it and I could not identify if there are some specific conditions when it does or does not happen. I can always scroll with the mouse wheel, so it does not seem to be an app freeze. But I cannot always grab the handle and drag it. MRE is below. I am on Windows 11, using PySide2. Not sure if the problem is on my machine (though what can be wrong for a scrollbar?) or in some way the scrollbar works. It is as if it's handle is not always active.

import sys
import os
from PySide2.QtGui import QPixmap, QIcon, QStandardItemModel, QStandardItem
from PySide2.QtWidgets import (
QApplication,
QWidget,
QVBoxLayout,
QListView,
)
from PySide2.QtCore import Qt, QDir, QSize


class Example(QWidget):
def __init__(self):
super().__init__()
self.layout = QVBoxLayout(self)

# File list view setup
self.file_list_view = QListView(self)
self.file_list_view.setFixedHeight(200)
self.layout.addWidget(self.file_list_view)

# File model
self.file_model = QStandardItemModel(self)
self.file_list_view.setModel(self.file_model)

# Custom scrollbar style
self.file_list_view.verticalScrollBar().setStyleSheet(
"""
QScrollBar:vertical {
width: 30px;
background-color: transparent;
border: none;
}
QScrollBar::handle:vertical {
background-color: rgb(100,100,100);
border-radius: 5px;
min-height: 50px;
}
QScrollBar::add-line:vertical, QScrollBar::sub-line:vertical {
border: none;
background: transparent;
}
QScrollBar::up-arrow:vertical, QScrollBar::down-arrow:vertical {
background: transparent;
}
"""
)

def populate_directory_view(self, dir_path):
self.file_model.clear()
self.dir_path = str(dir_path)

# Use os.listdir to get the file names (instead of QDir)
files = os.listdir(self.dir_path)
for file in files:
file_item = QStandardItem(file)
file_item.setTextAlignment(Qt.AlignCenter) # Center the text
file_item.setEditable(False)
self.file_model.appendRow(file_item)

# Set the view mode and remove icons
self.file_list_view.setViewMode(QListView.ListMode)
self.file_list_view.setIconSize(QSize(0, 0))

def reset(self):
self.file_model.clear()
self.dir_path = ""


if __name__ == "__main__":
app = QApplication(sys.argv)
viewer = Example()
viewer.show()

# Test directory path (use any valid directory on your machine)
test_directory = ... # Replace with your own test directory path
viewer.populate_directory_view(test_directory)

sys.exit(app.exec_())


Would be nice if a completely unrelated question would not be marked as duplicate of mine. I want to customize the handle.

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