Bugs and crash. wxpython 4.1.1

Windows 10
python 3.9.5

1.Run demo
2. Open Frames and Dialogs -> AUI_DockingWindowMgr
3. When you move the splitters a weird line shows up.

1.Open Advance Generic Widgets -> AUI

Drag the panes as shown in the image. As soon as drag begins, python crashes.


In my environment,
Windows 10 64bit
wxPython-4.1.1 (pypi)
Python 3.9.9
The first bug does not occur, but the second one does.
I used the debugger to get the following traceback:

Traceback (most recent call last):
  File "C:\Python39\lib\site-packages\wx\lib\agw\aui\framemanager.py", line 9288, in OnMotion
  File "C:\Python39\lib\site-packages\wx\lib\agw\aui\framemanager.py", line 9457, in OnMotion_ClickCaption
    e = self.FireEvent(wxEVT_AUI_PANE_FLOATED, self._action_pane, canVeto=False)
  File "C:\Python39\lib\site-packages\wx\lib\agw\aui\framemanager.py", line 9707, in OnMotion_DragFloatingPane
  File "C:\Python39\lib\site-packages\wx\lib\agw\aui\framemanager.py", line 6845, in UpdateDockingGuides
  File "C:\Python39\lib\site-packages\wx\lib\agw\aui\framemanager.py", line 4550, in CreateGuideWindows
    Host(AuiSingleDockingGuide(self._frame, wx.LEFT)))
  File "C:\Python39\lib\site-packages\wx\lib\agw\aui\framemanager.py", line 2246, in __init__
    useAero = GetManager(self.GetParent()).GetAGWFlags() & AUI_MGR_AERO_DOCKING_GUIDES
AttributeError: 'NoneType' object has no attribute 'GetAGWFlags'

Seems GetManager(self.GetParent()) -> None may be the cause of this issue.
Could you open this issue on GitHub?
When I have time, I will look into this.

Until this bug is fixed, the following styles can be alternatives.

        agwFlags = self._mgr.GetAGWFlags()
                               | aui.AUI_MGR_AERO_DOCKING_GUIDES
                               ## | aui.AUI_MGR_WHIDBEY_DOCKING_GUIDES

Confirmed that this problem is fixed in the latest snapshot wx 4.1.2a1.
Python 3.9.9 on Windows10 :ok_hand: