Pyqtgraph complains about weakref to scatter plot

[paulmueller]

There might be a missing parent not set somewhere. Is it related to when points are deleted?

[paulmueller]

Is this only happening on Windows?

[paulmueller]

Also:

Unhandled exception in CytoPlot version 2.25.4.0:
Traceback (most recent call last):
File "pyqtgraph\GraphicsScene\[GraphicsScene.py](http://graphicsscene.py/)", line 180, in mouseMoveEvent
File "pyqtgraph\GraphicsScene\[GraphicsScene.py](http://graphicsscene.py/)", line 293, in sendHoverEvents
File "[weakref.py](http://weakref.py/)", line 413, in delitem
KeyError: <weakref at 0x000001FC81877D80; to 'Handle' at 0x000001FC63318430>

[paulmueller]

A possible fix (added in 2.26.1) is to clear the hover event weak reference dictionary like so whenever the plot is modified: GraphicsScene.hoverItems.clear()