AxisItem.setMinimumSize (or setPreferredSize) not being respected

[Ognyan Moore]

I'm creating a plot with multiple AxisItems, that get resized occasionally, but I'm trying to preserve the value of the original width in the AxisItem.preferredWidth() property (or AxisItem.minimumWidth() 

Setting the value seems to have no effect.  The following assert code will fail.  Any help would be appreciated.

import pyqtgraph as pg
import sys
from pyqtgraph.Qt import QtGui, QtCore


class plotWidget(pg.GraphicsView):

    def __init__(self):
        super().__init__()
        self.layout = pg.GraphicsLayout()
        self.setCentralWidget(self.layout)

        self.main_plot = pg.PlotItem()
        ax = self.main_plot.getAxis('left')
        new_min_width = 100
        ax.setMinimumWidth(new_min_width)
        self.layout.addItem(self.main_plot)
        # assert test will fail
        assert ax.minimumWidth() == new_min_width



if __name__ == '__main__':
    pg.mkQApp()
    win = plotWidget()

    win.show()
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()