Does wxWindow.MakeModal(True) work for all Windows or just frames?

[mw]

I am using wxPython 2.6.3.0

As far as I can tell from the documentation (www.wxpython.org),
MakeModal() should work for all windows, but when I do some practical
tests, I can only get it to work for frames.

Can anyone confirm what the status of this method is.
Is it intended to work for all windows or just for frames?
If it is intended to work for all windows, does anyone have some sample
code to make a window within a frame modal (personally, I want to make
a grid modal).

/Magnus