PerformanceTest is incompatible with PyQtGraph 0.11

[tstenner]

Almost all examples run without issues (after i pip install pyqtgraph) but python PerformanceTest.py fails with

Created outlet with name BetaGen and type EEG
Created outlet with name GeneratedCentreOutMarkers and type Markers
looking for an EEG stream...
Reading from inlet named BetaGen with channels ['RAW1', 'SPK1', 'RAW2', 'SPK2', 'RAW3', 'SPK3'] sending data at 16384.0 Hz
Looking for stream with type Markers
Reading from inlet named GeneratedCentreOutMarkers with channels ['EventMarkers']
Traceback (most recent call last):
  File "PerformanceTest.py", line 308, in <module>
    qwindow.parent().setWindowTitle("pylsl PerformanceTest")
AttributeError: 'NoneType' object has no attribute 'setWindowTitle'

Edit: But i get the same error in master (l300), so it must be sth else than your changes. pyqtgraph==0.11.0

Originally posted by @agricolab in https://github.com/labstreaminglayer/liblsl-Python/pull/33#issuecomment-694803530

[agricolab]

PerformanceTest.py runs fine after pyqtgraph was uninstalled (with printouts), and with visualization after pip install pyqtgraph==0.10

[agricolab]

if haspyqtgraph:
    qapp = pg.QtGui.QApplication(sys.argv)
    qwindow = pg.plot(title="pylsl PerformanceTest")
    qwindow.clear()

runs with pyqtgraph==0.11 and pyqtgraph==0.10

Could be linked to the deprecation of PlotWindow? https://pyqtgraph.readthedocs.io/en/latest/graphicswindow.html#pyqtgraph.PlotWindow