Content is mirrored on Windows when system language is an RTL (right-to-left) language (e.g. Hebrew).
I guess this is because Windows mirrors every DC by default when system language is RTL.
When DC mirroring would be switched off in propgrid.cpp void wxPropertyGrid::DrawItems(...):
then text would be at least not mirrorred.
However, now the logic of the control would be left-to-right too (e.g. scrollbar on the right), instead of right-to-left, as other controls.
Also, there might be problems with word ordering, but I can't tell for sure as I don't know Hebrew at all.