Is it possible to set a width for a Widget without Fixing it?

I'm trying to set the width of a QScrollArea in PyQt5, but the only thing I found is setting the width through the

scroll.setFixedWidth(360)  

function.

The issue is when I put the scroll bar area in a QSplitter

self.splitter2 = QSplitter(Qt.Horizontal) 
self.splitter2.addWidget(scroll)

I cannot resize the scroll bar area width with the mouse any more.

What I would like to do is set the width of the scrollbar area (100 for instance) and be able to modify it afterwards when I click and drag the middle line of the QSplitter. For now it is one (set the width of the scrollbar area) or the other (modify the width with the mouse) - but not both at the same time.

Here's a minimal example:

from PyQt5.QtGui import *
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
import sys


class Viewer(QMainWindow):
    def __init__(self, parent=None):
        super(Viewer, self).__init__()
        self.parent = parent

        self.centralWidget= QWidget()
        self.setCentralWidget(self.centralWidget)
        self.mainHBOX = QHBoxLayout()
        self.setFixedWidth(200)
        self.setFixedHeight(200)

        label1 = QLabel('blablabalblablabalblablabalblablabalblablabalblablabalblablabalblablabalblablabal')
        label2 = QLabel('blablabal again')

        scroll = QScrollArea()
        scroll.setFixedWidth(100)
        scroll.setWidget(label1)
        scroll.setWidgetResizable(True)

        self.splitter2 = QSplitter(Qt.Horizontal)
        self.splitter2.addWidget(scroll)
        self.splitter2.addWidget(label2)

        self.mainHBOX.addWidget(self.splitter2)
        self.centralWidget.setLayout(self.mainHBOX)

def main():
    app = QApplication(sys.argv)
    ex = Viewer(app)
    ex.setWindowTitle('window')
    # ex.showMaximized()
    ex.show()
    sys.exit(app.exec_( ))


if __name__ == '__main__':
    main()

You should set the initial position of the splitter handle rather than setting the width of its child widgets. This can be done using QSplitter.setSizes:

leftwidth = 100
self.splitter2.setSizes([leftwidth, self.width() - leftwidth])

But note that the splitter won't allow moving its handle to a position less than the minimum width of a child widget. The default minimum width for a scroll-area is 100. So in the above example, setting leftwidth = 50 wouldn't work properly unless you explicitly reset the minimum width of the scroll-area accordingly.