[Pythoncard-users] does anyone know what this error means?

I'm sorry to email the list about this, but I'm at wit's end. I get
this error, which crashes most of my GUI, and I'm having days of
trouble isolating it. Does anyone have any clues on this?

wx._core.PyAssertionError, C++ assertion "m_count == -1" failed in .
.\..\src\msw\textctrl.cpp(122): wrong initial m_updatesCount value

Some things that might help:

- my program is multi threaded (4 threads in all)

- I'm on Windows

- the error only partially crashes the application. It's only effect
is in the GUI, but not the whole  GUI: the statusbar and menubar still
work fine, but the main window no longer repaints.

Any tips hugely appreciated.