Dietmar Schwertberger

I have tried this with wxWidgets and can see it there as well. I will have a look whether I can find the cause.

The fix is implemented in wxWidgets and will be part of wxWidgets 3.1.7.

I tried with two versions on my PC with sleep and hibernate and could not reproduce it. ``` sys.version: 3.7.9 (tags/v3.7.9:13c94747c7, Aug 17 2020, 18:58:18) [MSC v.1900 64 bit (AMD64)]...

I have just tried the script in a debugger on Windows. Incidentally, I picked two of my installations that are almost the same, just 32 vs. 64 bit. It seems...

I'm surprised that a pure wxPython script does not have issues with the `EVT_MOUSEWHEEL`. [wxPythonIssue1707_Panel.py.txt](https://github.com/wxWidgets/Phoenix/files/8173460/wxPythonIssue1707_Panel.py.txt)

OK, I have further tracked down the issue. matplotlib is storing references to wx events. If I modify backend_wx._FigureCanvasWxBase._onMotion: ` FigureCanvasBase.motion_notify_event(self, x, y, guiEvent=evt) ` to ` FigureCanvasBase.motion_notify_event(self, x, y,...

I have also built wxPython now and also don't see the issue.

As your example code from the first post on Discuss still fails, this might be a good starting point for debugging. https://discuss.wxpython.org/t/a-problem-with-event-objects/35766/2

Read Exception and backtrace look like this:  ``` > _core_d.cp310-win_amd64.pyd!meth_wxObject_GetClassInfo(_object * sipSelf, _object * sipArgs) Zeile 47 C++ python310_d.dll!cfunction_call(_object * func, _object * args, _object * kwargs) Zeile 552...

This might be related to a wxWidgets/wxPython sip interation. Anyway, not keeping a reference should fix the issue. See https://github.com/matplotlib/matplotlib/issues/22211#issuecomment-1065424567