I am having problems using Tk::MListbox on windows vista. The module works perfectly using the same version of ActivePerl on windows XP.

The problem I have found is to do with the callbacks used to update each Tk::Listbox that Tk::MListbox uses.

Firstly Tk::MListbox does not use Tk::Listbox directly, instead it derives Tk::CListbox from Tk::Listbox and adds the functionality to call a '-updatecommand' callback whenever something happens to it. The problem arises in the functions that initiate the '-updatecommand' callback.

It uses ($w being a reference to the Tk::CListbox object)

Under windows XP this will return a CODE reference to the Tk::Listbox selectionSet function. However, under windows vista this function will not return anything and causes the calling of this reference to throw an error:

Tk::Error: Not a CODE reference at C:/Perl/site/lib/Tk/MListbox.pm line 700.

I have checked the can function at it will work correctly for

referencing its own functions but fails with anything beginning with 'SUPER::'

Any ideas on why this is happening?